Multiple-termination routing in a wireless network environment with an internet protocol core

ABSTRACT

Methods for multiple-termination routing in a wireless network environment that includes an Internet Protocol (“IP”) core are described herein. One method includes receiving a call delivery request. The call delivery request includes a called number. The call features associated with the called number are determined. A determination is made whether the call features include multiple-termination routing information for a plurality of potential terminating devices. When the call features include the multiple-termination routing information including at least one termination to be routed utilizing Session Initiation Protocol (“SIP”), a call setup is initiated to each of the plurality of potential terminating devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This invention is a continuation application of U.S. patent application Ser. No. 11/352,757, entitled “Multiple-Termination Routing in a Wireless Network Environment with an Internet Protocol Core”, filed Feb. 13, 2006, which claims priority pursuant to 35 U.S.C. §119 (e) to U.S. Provisional Application Ser. No. 60/652,561, filed Feb. 14, 2005, and to U.S. Provisional Application Ser. No. 60/661,163, filed Mar. 11, 2005. U.S. patent application Ser. No. 11/352,757, U.S. Provisional Application Ser. No. 60/652,561, and U.S. Provisional Application Ser. No. 60/661,163 are all hereby incorporated by reference in their entirety as though fully and completely set forth herein.

BACKGROUND

1. Technical Field

The present invention relates generally to cellular wireless communication networks; and more particularly to mobile station operation in a legacy mobile station domain communication network.

2. Related Art

Cellular wireless networks include a “network infrastructure” that facilitates wireless communications with mobile terminals operating within a particular service coverage area. The network infrastructure couples to other network elements to support numerous types of communications, for example, the Public Switched Telephone Network (PSTN), the Internet, et cetera. The network infrastructure may route communications to other subscribing wireless units, to terminals coupled to the PSTN, to terminals coupled to the Internet, or to terminals coupled via another network to one of these networks.

Various wireless interface specifications have been developed to standardize wireless communications between the mobile terminals and the network infrastructure and between components that comprise the network infrastructure. Wireless interface specifications include, for example, the Advanced Mobile Phone Service (AMPS) specifications, the Global System for Mobile communications (GSM) specifications, the Code Division Multiple Access (CDMA) specifications, and the Time Division Multiple Access (TDMA) specifications. Generations of these specifications are generally referred to as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), et cetera. Each advancing generation of standards typically performs and/or supports a greater number of services, a greater number of features, and provides better communication qualities. These operating specifications may also be partially deployed from generation to generation, for example, 2G to 2.5G.

Some partial generation wireless specification updates may be deployed using a legacy infrastructure. For example, a 2.5G network has been deployed using upgraded components of a 2G network. When moving from one generation to another generation, however, the network infrastructure must typically be rebuilt using new infrastructure components.

Network infrastructure replacement is both expensive and difficult to deploy. An additional problem resulting from the generational replacement relates to backward compatibility of subscriber services. With 3G networks, for example, a subscriber subscribes to 3G services, which includes a suite of services. A 3G subscription may include, for example, circuit switched voice services for the subscriber's 2G mobile terminal, packet switched voice service for the subscriber's 3G packet switched mobile terminal, packet data services for the subscriber's personal data assistant, and packet data services for the subscriber's notebook computer, among other services. Each of the subscriber's wireless devices, however, may not be compatible with the 3G infrastructures.

In a typical next generation 3G infrastructure, legacy terminal support will be provided. When 3G systems are deployed, 3G mobile terminals will be placed into service. In such cases, the 3G infrastructures will support the 3G services for the 3G mobile terminals as they operate within the respective service areas. The 3G mobile terminals, however, must also be serviced while roaming into legacy 2G wireless networks. Thus backward compatibility issues arise that have not heretofore been addressed.

Further, 3G wireless terminals may be placed in service within a legacy network, and thus will be limited in their operation to certain services. If such a 3G wireless device roams from its home service area (that is, the area for which the subscriber normally obtains service) into a visiting service area that supports all 3G packet switched services, the 3G wireless device should not be allowed to receive services to which it does not subscribe. In such case, the visited network must prevent delivery of these services.

Thus, there is a need in the art for a system and method that may be employed to support services for both legacy mobile terminals and next generation mobile terminals operating within a next generation wireless communication systems and further to support services for next generation terminals operating within next generation networks for which the subscriber has subscribed to legacy networks based services.

SUMMARY

Provided is multiple-termination routing in a wireless network environment that includes an Internet Protocol (“IP”) core, where a call delivery request is received. The call delivery request is based upon intelligent network protocols and includes a called number. The call features associated with the called number are retrieved, and a determination is made whether the call features include multiple-termination routing information for a plurality of potential terminating devices. When the call features include multiple-termination routing information wherein at least one termination to be routed utilizes Session Initiation Protocol (“SIP”), independent call setups are initiated, concurrently or consecutively, to each of the plurality of potential terminating devices.

In a further aspect, when the call delivery request is a SIP INVITE, responding to the received call delivery request with a ringback message, wherein the ringback message instructs the sender of the call delivery request to generate ringback to the calling party terminating device.

In another aspect, the call setups are initiated consecutively to each of the plurality of potential terminating devices. A call setup leg is extended to the consecutively initiated call setups in response to a received provisional response, wherein the received provisional response provides call station information to be used for establishing a bearer path. Upon detecting a first potential terminating device to complete the call setup, initiation of a subsequent call setup (or setups) to the remaining terminating devices is foregone.

In yet another aspect, the call setup is concurrently initiated to each of the plurality of potential terminating devices concurrently initiating. A call setup leg is extended to each of the concurrently initiated call setups in response to a received provisional response, wherein the received provisional response provides call station information that is to be used for establishing a bearer path. Upon detecting a first potential terminating device to complete the call setup, the call setup is released to any of the remaining potential terminating devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a communication network formed according to an embodiment of the invention;

FIG. 2 is a functional block diagram of an MSCe according to an embodiment of the invention;

FIG. 3 is a functional block diagram of a multiple-termination call delivery to mobile stations according to an embodiment of the invention;

FIG. 4 is a signal flow diagram illustrating call delivery for concurrent multiple-termination routing according to one embodiment of the present invention;

FIG. 5 is a signal flow diagram illustrating the call feature retrieval of signaling steps of FIG. 4;

FIG. 6 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 4;

FIG. 7 is a signal flow diagram illustrating the session progress signal sequence of FIG. 4;

FIG. 8 is a signal sequence illustrating releasing the call setups to the remaining potential terminating devices of FIG. 4;

FIG. 9 is a functional block diagram of a multiple-termination call delivery with a mobile termination and a PSTN termination according to an embodiment of the invention;

FIG. 10 is a signal flow diagram 400 illustrating call delivery for concurrent multiple-termination routing including a mobile termination and a PSTN termination according to an embodiment of the invention;

FIG. 11 is a signal flow diagram illustrating retrieve call features of FIG. 10;

FIG. 12 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 10;

FIG. 13 is a signal flow diagram illustrating the detailed session progress signal sequence of FIG. 10;

FIG. 14 is a signal flow diagram illustrating the release of the call setups to the remaining potential terminating devices of FIG. 10;

FIGS. 15 a and 15 b are a signal flow diagram illustrating call delivery for consecutive multiple-termination routing according to an embodiment of the invention;

FIG. 16 is a signal flow diagram illustrating the retrieve call features signal sequence of FIG. 15 a;

FIG. 17 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 15 a;

FIG. 18 is a signal flow diagram illustrating the detailed session progress signal sequence of FIG. 15 a;

FIG. 19 is a signal sequence illustrating releasing the call setup of a potential terminating device of FIG. 15 a;

FIG. 20 is a signal flow diagram illustrating the next call features retrieval of signaling steps of FIG. 15 b;

FIG. 21 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 15 b;

FIG. 22 is a signal flow diagram illustrating the detailed session progress signal sequence of FIG. 15 b; and

FIG. 23 is a flow chart of a method for call delivery for consecutive multiple-termination routing according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a communication network formed according to an embodiment of the invention. The wireless communication network environment 10 is a next generational network that includes known components that, in addition to legacy network protocols (such as Integrated Services Digital Network User Part (“ISUP”), the call control portion of Signaling System 7), also utilizes the Internet Protocol (“IP”) as a network transport and IP-based call control protocols (for example, the Session Initiation Protocol (“SIP”)). The wireless communication network environment 10 may be employed to support both legacy mobile terminals and next generation mobile terminals within next generation wireless communication systems and further to properly service next generation terminals within next generation networks that have subscribed legacy networks services deploying legacy protocols in combination with IP-based signaling protocols that create additional complexity and processing obstacles to provide features that were taken for granted in legacy networks.

The communications network 10 includes a code division multiple access (“CDMA”) wireless access link that can use SIP and Internet Protocol (“IP”) for call origination and termination operations. An example of such a network is a Legacy Mobile Station Domain (“LMSD”). As one of ordinary in the skill would appreciate, other mobile wireless networks may be deployed. The wireless communications network is accessed with respect to the placement of a call to a mobile subscriber or by the initiation of a call by the mobile subscriber, and may be implemented by a variety of devices, such as a computer-based device, another mobile station, and/or a landline terminal.

Though a communications network may be modified and/or evolved to accommodate newer features, such as the multimedia data communications, support for maintaining legacy network features is also desired. For example, one such feature is multiple-termination routing, which allows a subscriber to be contacted simultaneously at multiple phone numbers, including home and office phones, mobile phones, and/or pagers, that are arranged and/or sequenced in a member list which contains information as to initiating concurrent and/or consecutive call setups with respect to the devices. Callers reach the subscriber by dialing a single called number. The call setup is completed on the first phone that answers, whether in a concurrent fashion that causes all of the members in the member list to be alerted, in a consecutive fashion where the members are successively alerted until a call is completed on the first phone that answers, and/or a mixture of concurrent and consecutive alerting. Completion of the call setup may occur through a subscriber answering the alerting terminal, through the alerting terminal entering a voice mail mode of operation, through a no-answer basis that allows the subscriber to determine how they want “no answer” calls to be handled, for example, forwarded to voice mail, et cetera.

The wireless communications network environment 10 includes a call initiation network 11, a packet network 22, a public switched telephone network (“PSTN”) 32, and an originating/serving network 13. The call initiation network supports calls initiated by the mobile station 12 and originating/serving network 13, supports the call terminating devices, mobile stations 40 and 46. The call initiation network 11 includes a mobile switching center emulation (“MSCe”) 18, a home location register/visitor location register 24, a base station 16, media gateway (“MGW”) 20 and a mobile station 12. The originating/serving network 13 includes MGW 26, base stations 36 and 42, an MSCe 28, a HLR/VLR 30, and mobile stations 40 and 46.

The call initiation network 11 and the originating serving network 13 interwork with other networks that include a packet network 22 and a public switched telephone network (“PSTN”) 32 which is coupled to a landline terminal 34. The packet network 22 and the PSTN 32 provide access to other networks and/or termination devices beyond those illustrated in the example provided.

The packet network 22 is a data network where data, arranged in a packet form, is routed between nodes over data links that may be shared between the nodes. An example of a packet network 22 include the Public Internet (which uses Internet Protocol (“IP”) based communications), Asynchronous Transfer Mode (“ATM”) based networks, et cetera.

The PSTN 32 is a network based upon circuit switching methodologies where dedicated connections between nodes are established for the duration of a communication dialog, such as with the local, long distance, and international phone systems. The PSTN uses intelligent network protocols for call delivery, such as the Signaling System No. 7 (“SS #7”). Intelligent networking is a method for providing and interpreting information within a distributed network. The North American variant of this protocol is referred to as “SS7” (without the “#”). The SS7 protocol employs a dedicated data circuit to carry packetized machine language messages about each call connected between and among machines of a network to achieve connection control. Intelligent network applications are built upon this protocol, and include call control and transaction capabilities that support database access as well as a variety of intelligent network functions and wireless telecommunications services.

With respect to wireless mobile communications networks (such as those under the TIA-136 and TIA-2000 specifications) utilize ANSI-41 as a signaling protocol that provides transaction-based operations to support subscriber mobility in the wireless telecommunications network. In the call initiation network 11, the base station 16, the MSC 18, MGW 20, and the HLR/VLR 24 provide subscriber mobility services to the mobile station 12. ANSI-41 allows a subscriber to move between networks while a call is in progress, allows subscribers to originate calls while roaming (that is, operating their mobile devices in a system other than the home system where the subscription was established), allows subscribers to receive calls while roaming, and allows subscribers to activate and use supplementary call features while roaming (for example, call forwarding).

A mobile station 12 is coupled to the call initiation network 11 through a base station 16 by the communication link 14. Communication link 14 is a wireless link. The base station 16 includes a base station controller and a base station transceiver (that is, radio receiver and transmitter) to provide the communication link 14. The base station 16 is further coupled to a mobile switching center emulation (MSCe) 18. The MSCe 18 provides the signaling functionality equivalent to that defined for a legacy MSC (that is, a 3GPP2 call control entity that only supports circuit-switched operations). Part of the signaling functionality supported by MSCe 18 includes the establishment, maintenance and termination of voice calls, the ability to modify an established call (for example, establishing three-way call after establishing a two-way call), and triggers to other network elements for the support of subscriber specific features (for example, prepaid calling). The MSCe 18 is coupled to the packet network 22 and the PSTN 32. The packet network 22 provides signaling connectivity (such as SIP connectivity) to other mobile communications networks, such as a LMSD network. The PSTN 32 provides signaling connectivity to landline devices, such as the landline terminal 34. The MGW 20 is coupled to base station 16, the packet network 22 and the PSTN 32.

The MGW 20 provides the bearer functionality for voice calls in the call initiation network 11. An example of bearer functionality includes the conversion of a voice data format, such as enhanced variable rate codec (“EVRC”), into another voice data format, such as ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) G.711. Such voice data formats are used when a voice call is established between the mobile station 12 through the base station 16, and the landline terminal 34 through the PSTN 32. Also, the MGW 20 supports the bearer traffic connectivity (for example, IP connectivity) to other mobile station communication networks, such as a LMSD, though packet network 22, and to landline devices through PSTN 32. The MGW 20 is also coupled to MSCe 18, which controls the bearer resources of MGW 20 through signaling (for example, the MEdia GAteway COntrol protocol (“MEGACO”) or the ITU-T recommendation for MEGACO, which is H.248). Generally, under MEGACO, the commands apply to terminations that are related to a “context.” A termination sources and/or sinks one or more streams of information. A context is an association between a collection of Terminations. The context describes the topology (that is who hear/sees whom) and the media mixing and/or switching parameters for the cases where more than two terminations are involved with this association Contexts are modified using the Add, Subtract, and Modify commands of H.248, with a connection created when two or more terminations are placed in a common context. The MSCe 18 retrieves subscriber and location information for the mobile stations it presently serves from the HLR/VLR 24.

With respect to the originating/serving network 13, the mobile station 40 communicates over a communication link 38 with a base station 36, and the mobile station 46 communicates over a communication link 44 to the base station 42. The base station 36 and the base station 42 access the MSCe 28 for supporting subscriber services. The MSCe 28 accesses the HLR/VLR 30 for subscriber and location information to mobiles stations it presently serves, such as mobile station 40 and mobile station 46. Though the MSCe 28 includes an Originating MSCe 48 and a Serving MSCe 50, the originating and serving components of the MSCe may exist as separate units. The multiple-termination routing operation and function of the Originating MSCe 48 will be described in detail with reference to FIGS. 3 through 23.

The MSCe 28 provides the signaling functionality to support subscriber services (for example, the delivery of a voice call to the mobile station 40). The MSCe 28 is coupled to the packet network 22 and the PSTN 32. For signaling connectivity (for example, SIP connectivity) to other mobile station communications networks, such as a LMSD, the packet network 22 is utilized. The PSTN 32 provides signaling connectivity (for example, Integrated Services Digital Network User Part (“ISUP”) connectivity) to landline devices, such as the landline terminal 34.

The MGW 26 provides the bearer functionality for voice calls in the originating/serving network 13. The MGW 26 is coupled to base station 36, the packet network 22 and the PSTN 32. The MGW 26 supports the bearer traffic connectivity (for example, IP connectivity) to other mobile station networks, such as a LMSD network, though the packet network 22 and to landline devices through the PSTN 32. The MGW 26 is also coupled to the MSCe 28, which controls the bearer resources of MGW 27 through signaling protocols (for example, MEGACO and/or H.248).

The MGW 27 also provides the bearer functionality for voice calls in the originating/serving network 13. The MGW 27 is coupled to base station 42, the packet network 22 and the PSTN 32. The MGW 27 supports the bearer traffic connectivity (for example, IP connectivity) to other mobile station networks, such as a LMSD network, though the packet network 22 and to landline devices through the PSTN 32. The MGW 27 is also coupled to the MSCe 28, which controls the bearer resources of MGW 27 through signaling protocols (for example, MEGACO and/or H.248).

In operation, when the mobile station 12 initiates a call to the mobile station 40 via its called number, the network 10 engages in the necessary signaling for termination routing to the mobile station 40. In the case where a multiple-termination routing is not present (that is, a one-to-many termination routing) the MSCe 18 configures the bearer resources in MGW 20, the base station 16, and mobile station 12 based upon information returned by MSCe 28.

With the wireless communication network environment 10, utilizing IP-based signaling protocols (for example, SIP) in combination with legacy network signaling protocols such as ANSI-41, additional complexity and processing exists to provide features otherwise taken for granted in legacy networks limited to deploying legacy signaling protocols such as ISUP and/or ANSI-41. The provisioning of multiple-termination routing involves accommodating the various subscriber services associated with a unique subscriber identifier (such as the Directory Number, the Mobile Identification Number, the Equipment Serial Number, etc.).

For example, for multiple-termination routing, if the called number placed by the mobile station 12 is associated with the mobile station 40, a multiple-termination routing feature may be present with respect to the call being completed with not only alerts mobile station 40 that a call from mobile station 12 is being attempted, but also alerts mobile station 46 and the landline terminal 34. The Originating MSCe 48 accommodates multiple-termination routing for the originating/serving network 13. In general, upon receiving a call delivery request 23 for a called number from the packet network 22 and/or a call delivery request 33 from the PSTN 32, the Originating MSCe 48 has the capability to access the subscriber feature subscription using the home location register 52 and the visitor location register 54 for call features associated with the called number in the call delivery request. The call features may include multiple-termination routing information as part of the subscriber feature subscription. When the call features include multiple-termination routing information, the MSCe 28 has the capability to initiate the multiple independent call setups to provide this subscriber feature accordingly.

FIG. 2 is a functional block diagram of the MSCe 28 that includes a processing module 60, a memory 62, a peripheral bus interface 70, and network interfaces 72 through 80. The processing module 60, in combination with operational instructions stored in memory 62 and accessed via the bus 61, executes MSCe functions. The MSCe functions include, but are not limited to, basic switching functions, call establishment coordination to and from wireless subscribers, transmission facilities management, mobility management, and/or call processing functions. The MSCe 28 may be implemented using a shared processing device, individual processing devices, or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on operational instructions. The memory 62 may be a single memory device or a plurality of memory devices. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, and/or any device that stores digital information.

The memory 62 can include a transcoder list 64, ringback logic 66, and operation logic 68. The operation logic includes logic for communicating through at least one network interface utilizing standardized protocols. The MSCe 28 includes a plurality of network ports labeled as network I/Fs (interfaces) 72-80. For intercommunication, the MSCe 28 receives a list of transcoders from a mobile station through one of the network interfaces 72-80, and the MSCe 28 forwards the list of transcoders through the network 10 through another interface of the network interface 72-80. The MSCe 28 also determines whether to generate a ringback or whether to allow another MSCe (such as MSCe 18) to generate ringback to the calling party. In the described embodiment, MSCe 28 includes operational logic that enables it to act as an Originating MSCe 48, and/or a terminating (serving) MSCe 50.

FIG. 3 is a functional block diagram of a multiple-termination call delivery 100 to mobile stations serviced by the base station 36 and the base station 42. The multiple-termination call delivery 100 includes an MSCe 28, a HLR/VLR 30, media gateways 26 and 27, and base station 36 that services mobile station 40, and base station 42 that services mobile station 46. The MSCe 28 includes a Serving MSCe 50 and an Originating MSCe 48. The Originating MSCe 48 provides the multiple-termination call delivery capability.

The HLR/VLR 30 includes a home location register 52 and a visitor location register 54. The HLR 52 and the VLR 54 may be located with each other, or as separate network elements. The home location register 52 is the location register to which a user identity is assigned for record purposes such as subscriber information. Subscriber information includes items such as location information, subscriber status, subscribed features, and directory numbers. An HLR may serve one or more MSCs and/or MSCes

The visitor location register 54 is the location register other than the HLR used by an MSC or MSCe to retrieve subscriber information for handling of services for a visiting subscriber. A service provider populates a visitor location register 54 initially, and is subsequently populated with visiting subscribers as they roam into, and out of, the coverage area served by the visitor location register 54. A visiting subscriber is a subscriber having services provided by a network outside of it home service area. The visitor location register 54 may serve one or more MSCs and/or MSCes.

The MSCe 28, in the present example, has an Originating MSCe 48 and a Serving MSCe 50. The “emulator” designation for the MSCe indicates the packet implementation of an MSC, though bearer data is not “switched” in the sense of a conventional MSC. The Originating MSCe 48 and the Serving MSCe 50 may be present in the same MSCe 28 or in a separate MSCe across a network. For simplicity of example, the originating and the Serving MSCe 50 are shown as being present in the MSCe 28. When a mobile station becomes operational within an area serviced by the MSCe 28, the visitor location register 54 temporarily stores subscriber information obtained from the home location register 52 that relates to the mobile station. The Serving MSCe 50 uses this subscriber information to provide services to the mobile station while it operates within the service coverage area of Serving MSCe 50.

In operation, a call delivery request 101, which includes a called number, is provided to the Originating MSCe 48. The Originating MSCe 48 may receive the call delivery request 101 from the packet network 22 (for example, the call delivery request 23 is a SIP INVITE request), or from the PSTN 32 (for example, the call delivery request 33 is an ISUP Initial Address Message (“IAM”)). In response to the call delivery request, the Originating MSCe 48 makes a request 102 to HLR/VLR 30 to obtain any call features associated with the called number and information as to how the Originating MSCe 48 should respond to the call setup request. The call features may include multiple-termination routing information. This information includes a member list and termination triggers. The member list provides a list of potential terminating devices, and may also designate the termination sequence for initiating the call sequence. The call sequence may be for consecutive call setups, concurrent call setups to each of the members, and/or a mixture thereof. In the present example, the members include mobile station 40 and mobile station 46, and the member list provides for concurrent, and/or consecutive, call setups to the terminating devices. Consecutive call setups are described in detail with reference to FIGS. 15 through 22. Based upon its subscriber information (for example location information), the home location register 52 retrieves termination information for the mobile station 40 at 104 a and 105 a, and for the mobile station 46 at 104 b and 105 b via the visitor location register 54. The HLR/VLR 30 returns call features associated with the called number in response 106.

Having retrieved the call features, the Originating MSCe 48 determines whether the call features include multiple-termination routing information to a plurality of potential terminating devices. Such determination, for example, is the presence of a TERMLIST parameter from an ANSI-41 location request response (“locreq”). When the call features include multiple-termination routing information, the Originating MSCe 48 initiates a call setup to each of the potential terminating devices. Using the routing information, the Originating MSCe can determine whether the terminating device is being served by another MSCe. When the terminating device is being served by an MSCe, the Originating MSCe 48 uses SIP for the call control protocol. In the present example both mobile station 40 and mobile station 46 are being served by the MSCe 48. Based upon the TERMLIST information, that is concurrent call setups, the Originating MSCe sends a SIP setup request at 107 a and at 107 b to the Serving MSCe 50.

Based upon internal information received while mobile station 40 and mobile station 46 are operating within the service area of the Serving MSCe 50, the Serving MSCe 50 attempts to contact the mobiles. The Serving MSCe 50 initiates an access setup to the base station 36 at 108 a and to the base station 42 at 108 b. After mobile 40 responses base station 36 send 109 a to the Serving MSCe 50. After mobile station 46 responses base station 42 sends 109 b to the Serving MSCe 50. In preparation for the call path with any of the mobile stations, the Serving MSCe 50 sends a signaling message 110 a, for example a H.248 ADD command, to the media gateway 27 to setup bearer resources to support a call setup to mobile station 46. The media gateway acknowledges the bearer resource setup with signaling message 111 a sent to the Serving MSCe 50. The Serving MSCe sends a signaling message 110 b, for example a H.248 ADD command, to the media gateway 26 to setup bearer resources to support a call setup to mobile station 40. The media gateway acknowledges the bearer resource setup with signaling message 111 b sent to the Serving MSCe 50.

The call setup status for each of the potential terminating devices, mobile station 42 and mobile station 46, is provided to the Originating MSCe 48 via the SIP setup ACK 112 a and 112 b. In this instance, the call setup is completed by the mobile station 40, as in having been “answered.” The base station 36 informs the Serving MSCe 50 by sending 113. In response to 113, SIP setup response 114 is sent to Originating MSCe. The Originating MSCe 48 completes the call setup by sending the call setup response 115 containing information about the first responder, mobile station 40. The Originating MSCe 48 releases the remaining potential terminating device, mobile station 46, and any bearer resources allocated to the call setup to mobile station 46.

FIG. 4 is a signal flow diagram 200 illustrating call delivery for concurrent multiple-termination routing via the base station 36 and the base station 42. Although the signal flow diagram 200 illustrates a concurrent multiple-termination routing for two mobile stations, one of ordinary skill in the art would appreciate that additional multiple-terminations may be used.

The SIP protocol is an IP based call control protocol set out by the Internet Engineering Task Force (“IETF”) Request-For-Comment (“RFC”) 3261. SIP-T is set out by IETF RFC 3372 regarding encapsulating ISUP messages (for example, as defined by ITU-T Q.763 or Alliance for Telecommunications Industry Solutions PP-1000113.2005) within SIP. ISUP messaging is used as circuit-switched (for example a SS7 based network) call control protocol. ISUP messaging is used to set-up, manage, and release trunk circuits that carry voice and data calls over a PSTN. The SIP-T/SIP convention is used to denote that a SIP message may include an encapsulated ISUP message. SIP-T/SIP messages may also include a payload. An example of a SIP payload is an SDP (Session Description Protocol) message. A SDP message, is a short structured textual description of the name and purpose of the session, and the media, protocols, codec (code/decode) formats, timing and transport information that are required to decide whether a session is likely to be of interest and to know how to start media tools to participate in the session. The information within a SDP message is set out in IETF RFC 2327.

For ANSI-41 commands, the ANSI-41 convention for operation component acronyms is used. For example, the Invoke component acronym is in all-capital letters (for example, “LOCREQ”), while the return result component acronym is in all-lowercase letters (for example, “locreq”). Also, IP terminals at the media gateways and the base stations are illustrated as numbers inside small ovals. The terminals are numbered for so that the various call segments may be more easily referenced. The description of FIGS. 4 through 8 and 10 through 23 is organized according to the particular events identified by corresponding numerical identifiers:

-   201 The Originating MSCe 48 receives an INVITE (per RFC 3261)     message that includes a SDP message, labeled SDP-4, and a called     number. The INVITE may include an encapsulated Initial Address     Message (“IAM”). The Originating MSCe 48 is the MSCe that owns the     called number dialed by the calling party (for example, mobile     station 12). -   202. The Originating MSCe 48 sends a LOCREQ to the home location     register 52 associated with called number. The Originating MSCe 48     may optionally include a TransactionCapability parameter to specify     the appropriate termination handling. -   203-10 The call features associated with the called number are     retrieved via the home location register 52. Retrieval of the call     features will be discussed in detail with reference to FIG. 5. -   211 When all routreqs are received by the home location register 52,     it returns a locreq to the Originating MSCe 48. The locreq includes     multiple-termination routing information in the form of the     TerminationList (“TERMLIST”) parameter, along with an indication of     the reason for extending the incoming call (that is, for     multiple-termination routing) in the DMH_RedirectionIndicator     (“REDIND”) parameter. The TerminationList parameter includes a     member list providing the plurality of potential terminating     devices, and termination triggers that indicates when to request     further instructions on call processing relating to each of the     devices where call setups are being initiated. In this scenario the     TerminationList member list includes two terminations: an     intersystem termination for the first member, mobile station 40, and     an intersystem termination for the second member, mobile station 46.     The information indicates the sequence of call processing     instructions to initiate a consecutive sequence of call setups. -   212 After receiving the locreq in signaling step 211, the     Originating MSCe 48 initiates a call setup to each of the plurality     of potential terminating devices (that is, mobile station 40 and     mobile station 46). Upon analyzing the intersystem termination     information the Originating MSCe 48 determines that both of the     intersystem terminations are associated with an MSCe and thus     SIP-T/SIP will be used for call setups to the MSCe serving the     termination-devices. For mobile station 40, the Originating MSCe 48     sends an INVITE message to the Serving MSCe 50 including Call-ID1,     TLDN1 (“Temporary Local Directory Number”) and SDP-4. The INVITE may     include an encapsulated ISUP IAM message. Note that the Originating     MSCe 48 may elect to modify SDP-4 as received in Step 201. Note that     this INVITE request is for the establishment of a Dialog between the     Originating MSCe 48 and the Serving MSCe 50 and is a different     Dialog than that related to the INVITE request of signaling step 201     received by the Originating MSCe 48. The dialog between Originating     MSCe 48 and the Serving MSCe 50 for a call setup to mobile station     40 is identified by Call-ID1. The Serving MSCe 50 will use TDLN1 to     make the association with MSID1 received in the ROUTREQ message     (FIG. 5, Step 204). -   213 After receiving the locreq at signaling step 211, for initiating     a call setup to the mobile station 46, the Originating MSCe 48 sends     an INVITE message to the Serving MSCe 50 including Call-ID2, TLDN2     and SDP-4. The INVITE may include an encapsulated ISUP IAM message.     Note that the Originating MSCe 48 may elect to modify SDP-4 that was     received in signaling step 201. Note that this INVITE request is for     the establishment of a Dialog between the Originating MSCe 48 and     the Serving MSCe 50 and is a different Dialog than that related to     the INVITE request of signaling step 201 received by the Originating     MSCe 48. The dialog between Originating MSCe 48 and the Serving MSCe     50 for a call setup to mobile station 46 is identified by Call-ID2.     The Serving MSCe 50 will use the TDLN2 to make the association with     MSID2 received in response to the ROUTREQ message (see FIG. 5, step     206). -   214 After receiving the locreq in signaling step 211, if the INVITE     request of signaling step 201 did not include an ISUP IAM Message,     the Serving MSCe 50 may send either a 180 Ringing message or a 183     Session Progress message to the originator of the INVITE request of     signaling step 201. The SIP informational class of responses “1xx”     is used to indicate call setup progress.     -   When the INVITE request at signaling step 201 includes an ISUP         IAM Message the Originating MSCe 48 may send either a 180         Ringing message or a 183 Session Progress message including an         ISUP Address Complete (“ACM”) message to the originator of the         INVITE request of signaling step 201.

If the Originating MSCe 48 elects to initiate local ringback (that is have ringback generated and sent to calling party by the originator of the INVITE request at signaling step 201), then a 180 Ringing message is sent to the originator of the INVITE request of signaling step 201; otherwise a 183 Session Progress message is sent. In this regard, when the call delivery request of signaling step 201 is a SIP INVITE, the Originating MSCe 48 responds to the received call delivery request with a ringback message that instructs the sender of the call delivery request to generate ringback to the calling party terminating device. For a call setup to a single terminating device, the Serving MSCe is serving the terminating device controls all aspects of ringback to the calling party. When multiple-termination routing is performed the control logic within Originating MSCe 48 controls all aspects of ringback to the calling party.

-   215 In response to the 180 Ringing or 183 Session Progress message,     a provisional acknowledgement (“PRACK”) message 215, is sent to the     Originating MSCe 48. PRACK is used to acknowledge receipt of a SIP     provisional response. In some scenarios, like voice calls, it is     critical that the network serving the called party known that the     call state information within a SIP provisional response has been     received by the network serving the calling party. The use of PRACK     is set out in IETF RFC 3262. -   216 The Originating MSCe 48 sends a 200 OK response to the PRACK     message, 215. The 200 OK response stops any retransmissions of the     PRACK message. -   217-22 The ringing management between the originating MSCe 48 and     the Serving MSCe 50 operates to permit sufficient time for the call     setups to the potential terminating devices, which in this example     are mobile stations 40 and 46. Ringing management 217-22 will be     discussed in detail with reference to FIG. 6. -   223-24 After receiving the INVITE message of signaling step 212, the     Serving MSCe 50 sends a PAGING REQUEST message (under the     Interoperability Specification (“IOS”) for CDMA2000 access network     interfaces) to the base station 36 to initiate a mobile terminated     call setup scenario for the mobile station associated with TLDN1     (that is, mobile station 40). The PAGING REQUEST message includes     the “Desired Codec” for the mobile station 40. The IOS protocol is     used to pass information between an MSCe and a Base Station (BS).     The messaging formats and procedures for this protocol are set out     in the 3GPP2 A.S0011-C through A.S0017-C, or updates revisions, of     these documents.     -   When the mobile station 40 responds to the page, a PAGING         RESPONSE message is sent from the serving base station 36 to the         Serving MSCe 50. The PAGING RESPONSE message includes the codec         chosen by the mobile station 40. The PAGING RESPONSE message may         include a list of available BS transcoders, and the connection         information, for example the IP address and port number, for the         base station 36 communications channel at termination 7. -   225-26 After receiving the INVITE message of signaling step 213, the     Serving MSCe 50 sends a PAGING REQUEST message to the base station     42 to initiate a mobile terminated call setup scenario for the     mobile station associated with TLDN2 (that is, mobile station 46).     The PAGING REQUEST message includes the “Desired Codec” for the     mobile station 46.     -   When a terminating mobile station responds to the page, a PAGING         RESPONSE message is sent from the serving base station 42 to the         Serving MSCe 50. The PAGING RESPONSE message includes the codec         chosen by the terminating mobile station 46. The PAGING RESPONSE         message may include a list of available base station         transcoders, and the connection information for the base station         42 communications channel at termination 11. -   227 With respect to the mobile station 40, the Serving MSCe 50     establishes a context with media gateway (“MGW”) 26. The H.248     message sent from the Serving MSCe 50 to MGW 26 includes two ADD     commands The first ADD command establishes a termination for a     bearer channel using RTP (“Real-time Transport Protocol”) towards     the packet network 22. The mode is set to sendrecv. If the Serving     MSCe 50 elects to initiate Termination-Side ringback (that is,     ringback sent to the calling party generated by the network     presently serving the called party), then ringback from termination     5 is initiated. The first ADD command includes a SDP-4, which is the     remote SDP including the connection information for the bearer     entity supporting the calling party (for example MGW 20 supporting a     call initiated by mobile station 12). Connection information may     include an IP Address and a User Datagram Protocol (“UDP”) Port     number.     -   Note that the ringback tone generated by the MGW 26 will not be         received by the calling party. As mentioned in step 214 the         Originating MSCe 48 controls all aspects of ringback to the         calling party for multiple-termination routing scenarios. The         bearer entity supporting the calling party will not allow         received data to be passed to the calling party until the bearer         entity is assured that the data is coming from a trusted source.         The Originating MSCe 48 controls the flow of all messaging to         the network entities support the calling party. It is only when         the Originating MSCe 48 sends a 200 OK (INVITE) including a SDP         (with the connection information of the trusted source) that is         in response to the SIP INVITE of signaling step 201 will the         bearer entity supporting the calling party will allow received         bearer data to be passed to the calling party.

The first ADD command may also contain a BT (Bearer Timer) parameter indicating, in seconds, the length of time MGW 26 waits without receiving data from the connection endpoint defined in SDP-4 before applying an error treatment to termination 5 (for example removing termination 5 from the bearer channel using RTP towards the packet network 22 and sending a message to the Serving MSCe 50 informing it of the action). The Serving MSCe 50, from the LEGINFO1 parameter in the Routereq message (signaling step 204), is aware that the call associated with TLDN1 is one termination of a multiple-termination routing scenario. In general the call setup time of a multiple-termination routing scenario is greater than the call setup time of a single termination scenario. The Serving MSCe 50 may, on a per call setup basis, adjust the value of BT based on knowledge it may have about the call setup.

The second ADD command establishes a termination for the base station 36 communication channel with a mode set to sendrecv (a bi-directional connection). The second ADD command includes SDP-7, which is the remote SDP including the base station 36 connection information (that is information sent in signaling step 224 that relates to termination 7).

-   228 The MGW 20 replies to the H.248 message of signaling step 227 by     sending a H.248 Reply message to the Serving MSCe 50. The Reply     message includes a SDP-5 and SDP-6. The SDP-5 is the local SDP for     the termination given in SDP-4 and includes the MGW 20 connection     information for termination 5. The SDP-6 is the local SDP for the     termination towards the base station 36 and includes the MGW 26     connection information (for example, the IP address and the UDP Port     number) for termination 6. -   229 With respect to the mobile station 46, the Serving MSCe 50     establishes a context with the MGW 27. The H.248 message sent from     the Serving MSCe 50 to MGW 27 includes two ADD commands. The first     ADD command establishes a termination for a bearer channel using RTP     towards the packet network 22. The termination mode is set to     sendrecv. If the Serving MSCe 50 elects to initiate Termination-Side     ringback, then ringback from termination 9 is initiated. The first     ADD command includes SDP-4, which is the remote SDP including the     connection information for the bearer entity supporting the calling     party (for example, the MGW 20 supporting a call initiated by the     mobile station 12). Connection information may include an IP Address     and a User Datagram Protocol (“UDP”) Port number).     -   Note that the ringback tone generated by the MGW 27 will not be         received by the calling party. As mentioned in step 214 the         Originating MSCe 48 controls all aspects of ringback to the         calling party for multiple-termination routing scenarios. The         bearer entity supporting the calling party will not allow         received data to be passed to the calling party until the bearer         entity is assured that the data is coming from a trusted source.         The Originating MSCe 48 controls the flow of all messaging to         the network entities that support the calling party. It is only         when the Originating MSCe 48 sends a 200 OK (INVITE) including a         SDP (with the connection information of the trusted source) that         is in response to the SIP INVITE of signaling step 201 will the         bearer entity supporting the calling party will allow received         bearer data to be passed to the calling party.

The first ADD command may also contain a BT (Bearer Timer) parameter indicating, in seconds, the length of time MGW 26 waits without receiving data from the connection endpoint defined in SDP-4 before applying an error treatment to termination 9 (for example removing termination 9 from the bearer channel using RTP towards the packet network 22 and sending a message to the Serving MSCe 50 informing it of the action). The Serving MSCe 50, from the LEGINFO2 parameter in the Routereq message (signaling step 206), is aware that the call associated with TLDN2 is one termination of a multiple-termination routing scenario. In general the call setup time of a multiple-termination routing scenario is greater than the call setup time of a single termination scenario. The Serving MSCe 50 may, on a per call setup basis, adjust the value of BT based on knowledge it may have about the call setup.

The second ADD command establishes a termination for the base station 42 communication channel with a termination mode set to sendrecv (a bi-directional connection). The second ADD command includes SDP-11, which is the remote SDP including the base station 42 connection information (that is information sent in signaling step 226 that relates to the termination 11 of the base station 42).

-   230 The MGW replies to the H.248 message of signaling step by     sending a H.248 Reply message to the Serving MSCe 50. The Reply     message includes SDP-9 and SDP-10. The SDP-9 is the local SDP for     the termination given in SDP 4 and includes MGW 27 connection     information for the termination 9. The SDP-10 is the local SDP for     the termination towards base station 42 and includes the connection     information (for example, IP address and UDP Port number) for     termination 10. -   231-36 The session progress signaling addresses the handshake     operation between the Serving MSCe 50 and the Originating MSCe 48.     The handshake operation between the Originating MSCe 48 and the     Serving MSCe 50 operates to provide connection management for the     call setups. The session progress signaling is not forwarded     through, as would occur with single termination call setups. The     session progress signaling 231-36 will be discussed in detail with     reference to FIG. 7. -   237 After receiving the Reply message of signaling step 228, the     Serving MSCe 50 sends an IOS Assignment Request message to the base     station 36 to request assignment of radio resources. The Assignment     Request message includes MGW 26 connection information (for     termination 6, obtained from signaling step 228), the request of any     base station 36 transcoding (if necessary) and the codec assignment     for the mobile station associated with TDLN1 (that is, mobile     station 40). -   238 After receiving an Assignment Request message at signaling step     237, the base station 36 sends the IOS Assignment Complete message     to the Serving MSCe 50. -   239 After receiving the Reply message at signaling step 230, the     Serving MSCe 50 sends an IOS Assignment Request message to the base     station 42 to request assignment of radio resources. The Assignment     Request message includes the MGW 27 connection information (for     termination 10, obtained from signaling step 230), the request of     any base station 42 transcoding (if necessary), and the codec     assignment for the mobile station associated with TDLN2 (that is,     mobile station 46). -   240 After receiving an Assignment Request message at signaling step     239, the base station 42 sends the IOS Assignment Complete message     to the Serving MSCe 50. -   241 Base station 36 sends a Connect message to the Serving MSCe 50     to indicate that the call has been answered by the mobile station     associated with TLDN1 (that is, mobile station 40). -   242 If the Serving MSCe 50 elected to initiate Termination-Side     ringback at signaling step 227, then the Serving MSCe 50 will send a     H.248 message to MGW 26. The H.248 message contains a MODIFY command     to deactivate Termination-Side ringback. -   243 The MGW 26 acknowledges the H.248 message of signaling step 242     by sending a H.248 Replay message to the Serving MSCe 50. -   244 After receiving the CONNECT message from the base station 36 and     the PRACK message is received at signaling step 232 (see FIG. 7),     the Serving MSCe 50 sends a 200 OK message to the Originating MSCe     48. The 200 OK message includes Call-ID1, which identifies to the     Originating MSCe 48 that mobile station 40 was the terminating     device completing the call setup. When the INVITE request from     signaling step 212 for the mobile station 40 includes an ISUP IAM     Message then the 200 OK message may include an ISUP Answer (“ANM”)     message. The 200 OK message acknowledges that the INVITE (signaling     step 212) message has succeeded. -   245 Upon receiving a 200 OK message from any one of the initiated     call setup requests (for example, the INVITE send in signaling step     212 to setup a call to the mobile station 40 or in signaling step     213 to setup a call to mobile station 46) the Originating MSCe 48     sends a 200 OK message to the originator of the INVITE request     (signaling step 201). The 200 OK message including SDP-5 (that is     the SDP received in signaling step 231 (see FIG. 7). The 200 Ok     message includes SDP-5, instead of SDP-9, for the 200 OK message in     signaling step 244 included Call-ID1. When the INVITE request from     the initiating network at step 201 includes an ISUP IAM Message,     then the 200 OK message may include an ANM message. The 200 OK     message acknowledges that the INVITE at signaling step 201 message     has succeeded. -   246 The Originating MSCe 48 receives an ACK message. The ACK message     confirms reception of the final response (that is, 200 OK at     signaling step 245) for the Dialog identified by Call-ID0. -   247 Upon receiving an ACK message at signaling step 246 for the     Dialog identified by Call-ID0, the Originating MSCe 48 sends an ACK     message to the Serving MSCe 50 to confirm reception of the final     response (that is, 200 OK in signaling step 244) for the Dialog     identified by Call-ID1. -   248-54 Upon detecting the first potential terminating device to     complete the call setup, in this instance mobile station 40, any     call setups to remaining potential terminating device or devices are     released. The release signaling steps 248-54 will be discussed in     detail with reference to FIG. 8.

FIG. 5 is a signal flow diagram illustrating the call feature retrieval of signaling steps 203-210 of FIG. 4.

-   203-06 The home location register 52 recognizes the called number as     having a multiple-termination routing feature, and that, based on     the received TransactionCapability parameter, received in signaling     step 202, the Originating MSCe 48 is capable of supporting a     multiple-termination call. In this scenario, there are the two     Mobile Station Identifiers (MSIDs) in the member list are registered     in the same system; therefore, two ROUTREQs are sent to the Serving     visitor location register 54, and the visitor location register 54     forwards the ROUTREQs to the Serving MSCe 50. The MSID is a private,     unique identification of the subscriber. -   208-10 In reaction to each ROUTREQ, the Serving MSCe 50 checks its     internal data structures and determines that the mobile stations 40     (associated with MSID1) and mobile station 46 (associated with     MSID2) are currently idle (or in similar call-ready states, such as     the call is involved in another call, but has a call waiting     feature). The Serving MSCe 50 then allocates two TLDNs. TLDN1 is     associated with MSID1 and TLDN2 is associated with MSID2. The TLDN     values are returned to the visitor location register 54 in a     routreq. The visitor location register 54 sends each routreq to the     home location register 52.

FIG. 6 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 4. In this sequence of step the Originating MSCe 48 receives the SIP provisional responses, indicating that the call setups to mobile station 40 and mobile station 46 are proceeding, from Serving MSCe 50 and acknowledges there reception with SIP PRACK. messages. Unlike a single termination scenario, when the Originating MSCe 48 receives any 18x messages from Serving MSCe 50, for example indicating a desire for local ringback, the 18x messages are terminated (that is not forward onward) by Originating MSCe 48:

-   217 After receiving the INVITE for a call setup to the mobile     station 40 at signaling step 212, if the INVITE request did not     include an ISUP IAM Message, the Serving MSCe 50 may send either a     180 Ringing message or a 183 Session Progress message to the     Originating MSCe 48     -   When the INVITE request includes an ISUP IAM Message, the         Serving MSCe 50 may send either a 180 Ringing message or a 183         Session Progress message including an ISUP ACM message to the         Originating MSCe 48. The purpose of the ISUP ACM message is to         stop any timers in the Originating MSCe 48 that might be         associated with the ISUP IAM sent in signaling step 212.     -   If the Serving MSC 50 elects to initiate local ringback then the         180 Ringing message is sent. -   218 In response to the 180 Ringing message or a 183 Session Progress     message at signaling step 217, a PRACK message is sent to the     Serving MSCe 50. -   219 The Serving MSCe 50 sends a 200 OK response to the Originating     MSCe 48 in response to the PRACK message at signaling step 218. -   220 After receiving the INVITE for the mobile station 46 at     signaling step 213, if the INVITE request did not include an ISUP     IAM Message the Serving MSCe 50 may send either a 180 Ringing     message or a 183 Session Progress message to the Originating MSCe 48     -   When the INVITE request includes an ISUP IAM Message, the         Serving MSCe 50 may send either a 180 Ringing message or a 183         Session Progress message including an ISUP ACM message to the         Originating MSCe 48. The purpose of the ISUP ACM message is to         stop any timers in the Originating MSCe 48 that might be         associated with the ISUP IAM sent in signaling step 213. The         Originating MSCe 48 does not forward the 180 Ringing message         and/or the 183 Session Progress message, as may the case in         single-termination call setups.     -   If the Serving MSC 50 elects to initiate local ringback then the         180 Ringing message is sent. -   221 In response to the 180 Ringing message or a 183 Session Progress     message at signaling step 220, a PRACK message is sent to the     Serving MSCe 50. -   222 The Serving MSCe 50 sends a 200 OK response to the Originating     MSCe 48 in response to the PRACK message from signaling step 221.

FIG. 7 is a signal flow diagram illustrating the session progress signal sequence of FIG. 4. The Originating MSCe 48 coordinates the multiple-termination routing for connection management. In this sequence of signaling steps, the Originating MSCe 48 receives the SIP provisional responses, indicating that the call setups to mobile station 40 and mobile station 46 are proceeding, from Serving MSCe 50 and acknowledges there reception with SIP PRACK messages. Unlike a single termination scenario the Originating MSCe stores any information received, for example SDP messages, in the SIP provisional responses and does not act. When the Originating MSCe 50 receives information as to which terminating device will actually complete the call setup (signaling step 244 which includes Call-ID1) does the Originating MSCe 50 retrieve the appropriate stored information and send it to the signaling entity supporting the calling party.

-   231 Upon receiving a Reply message in signaling step 228, the     Serving MSCe 50 sends the Originating MSCe 48 a 183 Session Progress     message including SDP-5.     -   Note the 183 Session Progress message is not sent to the         originator of the INVITE message, signaling step 201. -   232 In response to the 183 Session Progress message from signaling     step 231, the Originating MSCe 48 stores SDP-5 and sends a PRACK     message to the Serving MSCe 50. -   233 The Serving MSCe 50 sends a response to the PRACK message from     signaling step 232 to the Originating MSCe 48. -   234 Upon receiving a Reply message in signaling step 230, the     Serving MSCe 50 sends the Originating MSCe 48 a 183 Session Progress     message including SDP-9.     -   Note the 183 Session Progress message is not sent to the         originator of the INVITE message, signaling step 201. -   235 In response to the 183 Session Progress message from signaling     step 234, the Originating sends a PRACK message to the Serving MSCe     50. -   236 The Serving MSCe 50 sends a response to the PRACK message from     signaling step 235 to the Originating MSCe 48.

FIG. 8 is a signal sequence illustrating releasing the call setups to the remaining potential terminating devices of FIG. 4:

-   248 Upon receiving a 200 OK in signaling step 244, the Originating     MSCe 48 releases all other call setup attempts. The Originating MSCe     48 sends an IOS CANCEL message to the Serving MSCe 50. If the INVITE     request for the mobile station 46 in signaling step 213 included an     ISUP IAM Message, then the CANCEL message may contain a REL message. -   249 The Serving MSCe 50 sends a 487 Request Terminated message to     the Originating MSCe 48. The Message is a response to the INVITE     request from signaling step 213. -   250 The Serving MSCe 50 answers the CANCEL request for the mobile     station 46 in signaling step 248 by sending a 200 OK message to the     Originating MSCe 48. -   251 Upon receiving the CANCEL message of signaling step 248 from the     Originating MSCe 248, the Serving MSCe 50 begins releasing all     resources associated with the call setup attempt to the mobile     station 46. The Serving MSCe 50 sends the MGW 27 a H.248 message     consisting of two SUBTRACT commands. The first SUBTRACT command     removes termination 10 to base station 42. The second SUBTRACT     removes termination 9 for the bearer channel using RTP towards the     packet network 22. -   252 The MGW 27 replies to the H.248 message at signaling step 251 by     sending Serving MSCe 50 with a H.248 Reply message. -   253 Upon receiving the CANCEL message at signaling step 248 from the     Originating MSCe 48, the Serving MSCe 50 sends a Clear Command to     the base station 42 to instruct the base station 42 to release the     associated dedicated resources. -   254 The base station 42 sends a Clear Complete message to the     Serving MSCe 50. The Serving MSCe 50 releases the underlying     transport connection.

FIG. 9 is a functional block diagram of a multiple-termination call delivery 100 to a mobile station serviced by the base station 36 and a landline terminal serviced by the PSTN 32. In operation, a call delivery request 301, which includes a called number, is provided to the Originating MSCe 48. The Originating MSCe 48 may receive the call setup request 301 from the packet network 22 (for example, the call delivery request 23 is a SIP INVITE request), or from the PSTN 32 (for example, the call delivery request 33 is an ISUP IAM). In response to the call delivery request, the Originating MSCe 48 makes a request 302 to HLR/VLR 30 to obtain any call features associated with the called number and information instruction the nature in which the Originating MSCe 48 should response to the call delivery request. The call features may include multiple-termination routing information, which includes a member list and termination triggers. The member list provides a list of potential terminating devices, and the termination triggers indicate when to request further instructions on call processing relating to each of the devices where call setups are being initiated. The information also provides the call setup sequence with respect to the list of potential terminating devices. The call sequence may be for consecutive call setups to each of the members, concurrent call setups to each of the members, and/or a mixture thereof.

In the present example, the member list includes mobile station 40 and the landline terminal 34, and provides for concurrent call setups. Based upon its subscriber information (for example location information), the home location register 52 retrieves termination information for the mobile station 40 at steps 304 and 305 via the visitor location register 54. The HLR/VLR 30 returns call features associated with the called number in response 306.

Having retrieved the call features, the Originating MSCe 48 determines whether the call features include multiple-termination routing information to a plurality of potential terminating devices. The Originating MSCe 48 uses the routing information to determine whether the terminating device is being served by another MSCe, a legacy MSC, or if neither, by the PSTN 32. If the terminating device is being served by an MSCe, the Originating MSCe 48 will use SIP for the call control protocol. If the routing is to the PSTN 32, the originating MSCe uses ISUP for the call control protocol. In the present example, a MSCe serves the mobile station 40 The Originating MSCe 48 sends a SIP setup request 307 a to the Serving MSCe 50 to attempt a call setup with mobile station 40. The Originating MSCe 48 sends signaling message 307 b, for example a H.248 ADD command, to the media gateway 27 to setup bearer resources to support a call setup to landline terminal 34. The media gateway 27 acknowledges the bearer resource setup with signaling message 307 c sent to the Originating MSCe 50. Using the information received in signaling message 307 c, the Originating MSCe 48 sends ISUP signaling, for example an ISUP IAM, to PSTN 32 to attempt a call setup with landline terminal 34.

With respect to the mobile station 40, the Serving MSCe 50, initiates an access setup to the base station 36 at 308. After mobile 40 responds, base station 36, at 309, sends an access setup to the Serving MSCe 50. In preparation for the call path with the mobile station 40, the Serving MSCe 50 sends a signaling message at 310, for example, a H.248 ADD command, to the media gateway 26 to set up the bearer resources to support a call setup to the mobile station 40. The media gateway 26 acknowledges the bearer resource setup with a signaling message at step 311.

The call setup status for mobile station 42 and is provided to the Originating MSCe 48 via the SIP setup ACK at step 312 a. The call status for landline terminal 34 is provided to the Originating MSCe 48 via ISUP at step 312 b. In this instance, the call setup is completed by the mobile station 40, as in having been answered. The base station 36 informs the Serving MSCe 50 at step 313. In response to 313, the SIP setup response at 314 is sent to the Originating MSCe 48 from the Serving MSCe 50. The Originating MSCe 48 completes the call setup by sending the call setup response at step 315 that includes information about the first responder—in this example, mobile station 40. The Originating MSCe 48 releases the remaining potential terminating device, landline terminal 34, and any bearer resources (for example, those bearer resources in Media Gateway 27) that were allocated to the call setup to the landline terminal 34.

FIG. 10 is a signal flow diagram 400 illustrating call delivery for concurrent multiple-termination routing via the base station 36 and the PSTN 32. For purposes of this example, the mobile station 40, serviced by the base station 36, is presently served by a MSCe other than the Originating MSCe 48. The Originating MSCe 48 is defined as the home MSCe for the called number from the initiating device. Because the second member of the member list is a PSTN directory number, a media gateway 27 is required in the originating/serving network 13 to support the PSTN call setup. In this example, the mobile station 40 completes (that is, answers) the call setup first and thus the PSTN call setup is abandoned:

-   401. The Originating MSCe 48 receives an INVITE message including a     SDP message labeled SDP-4 and a called number. The INVITE may     contain an encapsulated ISUP IAM. -   402. The Originating MSCe 48 sends a LOCREQ to the HLR associated     with the called number. The Originating MSCe 48 may optionally     include the TransactionCapability parameter to specify the     appropriate termination handling. -   403-06 The call features associated with the called number are     retrieved via the HLR 52. Retrieval of the call features will be     discussed in detail with reference to FIG. 11. -   407 When all routreqs are received by the home location register 52,     it returns a locreq to the Originating MSCe 48. The locreq includes     multiple-termination routing information in the form of the     TerminationList parameter (“TERMLIST”), along with an indication of     the reason for extending the incoming call (that is, for     multiple-termination routing) in the DMH_RedirectionIndicator     (“REDIND”) parameter. The TerminationList parameter includes a     member list providing the plurality of potential terminating     devices, and termination triggers that indicate when to request     further instructions on call processing relating to each of the     devices where call setups are being initiated. In this scenario the     TerminationList parameter includes two terminations: an intersystem     termination for the first member of the member list, and a PSTN     termination for the second member of the member list. -   408 After receiving the locreq at signaling step 407, the     Originating MSCe 48 initiates a call setup to each of the plurality     of potential terminating devices (that is, mobile station 40 and the     landline terminal 34). Upon analysis of the intersystem termination     information, the Originating MSCe 48 determines that the intersystem     termination is associated with an MSCe. Accordingly, the call setup     uses SIP-T/SIP with the MSCe serving the termination device. The     Originating MSCe 48 sends an INVITE message to the Serving MSCe 50     including Call-ID1, TLDN1 and SDP-4 to setup a call to the first     member of the member list (that is, the mobile station 40). The     INVITE may contain an encapsulated ISUP IAM message. Note that the     Originating MSCe 48 may elect to modify SDP-4 from that received in     signaling step 401. Note that this INVITE request is for the     establishment of a Dialog between the Originating MSCe 48 and the     Serving MSCe 50 and is a different Dialog than that related to the     INVITE request (see signaling step 401) received by the Originating     MSCe 48. The dialog between Originating MSCe 48 and the Serving MSCe     50 for a call setup to mobile station 40 is identified by Call-ID1.     The Serving MSCe 50 will use TDLN1 to make the association with     MSID1 received in the ROUTREQ message of signaling step 404 (see     FIG. 11). -   409 After receiving the locreq at signaling step 407, the     Originating MSCe 48 establishes a context with the MGW 27.     -   Note that the reason the Originating MSCe 48 establishes a         context with the MGW 27 is because the TerminationList parameter         received in signaling step 407 included a PSTN termination, and         the Originating MSCe 48 determined that ISUP must be used for         the call setup. If the Originating MSCe 48 had determined that         SIP could have been used for the call setup then there would be         no requirement to have bearer resources allocated in MGW 27 for         this termination.     -   The H.248 message sent from the Originating MSCe 48 to the MGW         27 includes two ADD commands. The first ADD command establishes         termination 8 for a bearer channel using RTP towards the packet         network 22. The first ADD command includes a SDP-4, which is the         remote SDP including the connection information for the bearer         entity supporting the calling party (for example MGW 20         supporting a call initiated by mobile station 12). Connection         information may include an IP Address and a User Datagram         Protocol (“UDP”) Port number.     -   The first ADD command may also contain a BT (Bearer Timer)         parameter indicating, in seconds, the length of time MGW 27         waits without receiving data from the connection endpoint         defined in SDP-4 before applying an error treatment to         termination 8 (for example removing termination 8 from the         bearer channel using RTP towards the packet network 22 and         sending a message to the Originating MSCe 48 informing it of the         action). The Originating MSCe 48, from the TERMLIST parameter in         the locreq message (signaling step 407), is aware that the call         setup is one termination of a multiple-termination routing         scenario. In general the call setup time of a         multiple-termination routing scenario is greater than the call         setup time of a single termination scenario. The Originating         MSCe 50 may, on a per call setup basis, adjust the value of BT         based on knowledge it may have about the call setup.     -   The second ADD command establishes termination 9 for a PSTN         communication channel (for example, DS0 on a T1 or E1 line) with         a mode set to recvonly (or sendrecv). -   410 The MGW 27 replies to the H.248 message of signaling step 409,     by sending the Serving MSCe 50 a H.248 Replay message. The H.248     Reply message includes SDP-8, the local SDP for the MGW 27. SDP-8     includes connection information, such as an IP address, a UDP Port     number, and a list of Codecs that the MGW 27 supports for sending     and receiving. -   411 The Originating MSCe 48 sends an ISUP IAM to setup a call to the     second member of the member list (that is, the PSTN directory number     corresponding to the landline terminal 34). -   412 After receiving the locreq in signaling step 407, if the INVITE     request of signaling step 401 did not contain an ISUP IAM Message,     the Serving MSCe 50 may send either a 180 Ringing message or a 183     Session Progress message to the originator of the INVITE request     (signaling step 401).     -   When the INVITE request in signaling step 401 includes an ISUP         IAM Message, the Originating MSCe 48 may send either a 180         Ringing message or a 183 Session Progress message including an         ISUP ACM (Address Complete Message) message to the originator of         the INVITE request at signaling step 401.     -   If the Originating MSCe 48 elects to initiate local ringback,         then a 180 Ringing message is sent; otherwise a 183 Session         Progress message is sent. For a call setup to a single         terminating device the MSCe (or the serving exchange for a         landline terminal device) that is serving the terminating device         controls all aspects of ringback to the calling party. When         multiple-termination routing is performed the control logic         within Originating MSCe 48 controls all aspects of ringback to         the calling party. Accordingly, in this message exchange, when         the call delivery request of signaling step 401 is a SIP INVITE,         the Originating MSCe 48 may respond to the received call         delivery request with a ringback message that instructs the         sender of the call delivery request to generate ringback to the         calling party terminating device. -   413 In response to the 180 Ringing or 183 Session Progress message,     a PRACK message is sent to the Originating MSCe 48. -   414 The Originating MSCe 48 sends a 200 OK response to the PRACK     message (signaling step 413). -   415-17 The ringing management between the originating MSCe 48 and     the Serving MSCe 50 prevents the Serving MSCe 48 from controlling     local ringback to the calling party. Ringing management 415-17 will     be discussed in detail with reference to FIG. 12. -   418 The Originating MSCe 48 receives an ISUP ACM associated with the     PSTN call setup to landline terminal 34. -   419 After receiving an INVITE message in signaling step 408, the     Serving MSCe 50 sends a PAGING REQUEST message to initiate a mobile     terminated call setup scenario for the mobile station associated     with TLDN1 (that is, mobile station 40). The PAGING REQUEST message     includes the “Desired Codec” for the mobile station 40. -   420 When the terminating mobile station responds to the page, a     PAGING RESPONSE message is sent from the base station 36 to the     Serving MSCe 50. The PAGING RESPONSE message includes the codec     chosen by the mobile station 40. The PAGING RESPONSE message may     contain a list of available BS transcoders, and the connection     information for the base station 36 communications channel at     termination 7. -   421 The Serving MSCe 50 establishes a context with a MGW 26. The     H.248 message sent from the Serving MSCe 50 to the MGW 26 includes     of two ADD commands. The first ADD command establishes a termination     for a bearer channel using RTP towards the packet network 22. The     mode is set to sendrecv. If the Serving MSCe 50 elects to initiate     Termination-Side ringback, then ringback from termination 5 is     initiated. SDP-4 is the remote SDP including the connection     information for the bearer entity supporting the calling party (for     example MGW 20 supporting a call initiated by mobile station 12),     Connection information may include an IP Address and a User Datagram     Protocol (“UDP”) Port number).     -   Note that any ringback tone generated by the MGW 26 will not be         received by the calling party. As mentioned with respect to         signaling step 412 the Originating MSCe 48 controls all aspects         of ringback to the calling party for multiple-termination         routing scenarios. The bearer entity supporting the calling         party will not allow received data to be passed to the calling         party until the bearer entity is assured that the data is coming         from a trusted source. The Originating MSCe 48 controls the flow         of all messaging to the network entities support the calling         party. It is only when the Originating MSCe 48 sends a 200 OK         (INVITE) including a SDP (with the connection information of the         trusted source) that is in response to the SIP INVITE of         signaling step 201 will the bearer entity supporting the calling         party will allow received bearer data to be passed to the         calling party. The second ADD command establishes a termination         for the base station 36 communication channel with a mode set to         sendrecv. The second ADD command includes SDP-7, which is the         remote SDP including the base station connection information         (that is, information sent in signaling step 420 that relates to         termination 7).     -   The first ADD command may also contain a BT (Bearer Timer)         parameter indicating, in seconds, the length of time MGW 26         waits without receiving data from the connection endpoint         defined in SDP-4 before applying an error treatment to         termination 5 (for example removing termination 5 from the         bearer channel using RTP towards the packet network 22 and         sending a message to the Serving MSCe 50 informing it of the         action). The Serving MSCe 50, from the LEGINFO1 parameter in the         Routereq message (signaling step 404), is aware that the call         associated with TLDN1 is one termination of a         multiple-termination routing scenario. In general the call setup         time of a multiple-termination routing scenario is greater than         the call setup time of a single termination scenario. The         Serving MSCe 50 may, on a per call setup basis, adjust the value         of BT based on knowledge it may have about the call setup. -   422 The MGW 26 replies to the H.248 message of signaling step 421 by     sending the Serving MSCe 50 an H.248 Reply message. The Reply     message includes SDP-5 and SDP-6. SDP-5 is the local SDP for the     termination (identified by the connection information) given in SDP     4, and includes the MGW 26 connection information for termination 5.     SDP-6 is the local SDP for the termination towards the base station     36 and includes the connection information (for example, IP address     and UDP Port number) for termination 6. -   423-25 The session progress signaling addresses the handshake     operation between the Serving MSCe 50 and the Originating MSCe 48.     The session progress interaction of the Originating MSCe 48 with the     Serving MSCe 50 operates to provide connection management for the     call setups. The session progress signaling 423-25 will be discussed     in detail with reference to FIG. 13. -   426 After receiving the Reply message at signaling step 422, the     Serving MSCe 50 sends an IOS Assignment Request message to the base     station 36 to request assignment of radio resources. The Assignment     Request message includes the MGW 26 connection information (for     termination 6, obtained from signaling step 422), request of any     base station transcoding (if necessary) and the codec assignment for     the mobile station 40 associated with TDLN1. -   427 After receiving an IOS Assignment Request message at signaling     step 427, the base station 36 sends the IOS Assignment Complete     message to the Serving MSCe 50. -   428 The base station 36 sends a CONNECT message to the Serving MSCe     50 to indicate that the call has been answered by the mobile station     associated with TLDN1 (that is, mobile station 40). -   429 If the Serving MSCe 50 elected to initiate Termination-Side     ringback (in signaling step 421), then the Serving MSCe 50 will send     a H.248 message to MGW 26. The H.248 message includes a MODIFY     command to deactivate Termination-Side Ringback. -   430 The MGW 26 acknowledges the H.248 message of signaling step 429     with a H.248 Reply message sent from MGW 26 to Serving MSCe 50. -   431 After receiving the CONNECT message from the base station 36 and     the PRACK message (see FIG. 13, signaling step 424) is received, the     Serving MSCe 50 sends a 200 OK message to the Originating MSCe 48.     When the INVITE request at signaling step 408 includes an ISUP IAM     Message, then the 200 OK message may contain an ISUP ANM (Answer     Message) message. The 200 OK message acknowledges that the INVITE     message from signaling step 408 has succeeded. In this manner, the     Originating MSCe 48 detects a first potential terminating device to     complete the initiated call setup. -   432 Upon receiving a 200 OK message or an ISUP ANM message from any     one of the call setup requests (for example, from the INVITE message     of signaling step 408 or the ISUP IAM in signaling step 411) the     Originating MSCe 48 sends a 200 OK message to the originator of the     INVITE request of signaling step 401. Since the intersystem     termination (that is, the mobile station 40) answered first, the 200     OK message includes SDP-5 (that is, the SDP received in signaling     step 423). When the INVITE request from signaling step 401 includes     an ISUP IAM message, then the 200 OK message may contain an ISUP ANM     message. The 200 OK message acknowledges that the INVITE request     from signaling step 401 message succeeded.     -   Note that if the PSTN termination answered first, then the 200         OK message would contain the SDP-8 received in signaling step         410. -   433 The Originating MSCe 48 receives an ACK message. The ACK message     confirms reception of the final response (that is, the 200 OK from     signaling step 432) for the Dialog identified by Call-ID0. -   434 Upon receiving an ACK message in signaling step 433, the     Originating MSCe 48 sends an ACK message to the Serving MSCe 50 to     confirm reception of the final response (that is, the 200 OK from     signaling step 431) for the Dialog identified by Call-ID1. -   435-38 Upon detecting a first potential terminating device to     complete the call setup, any call setups to remaining potential     terminating device or devices are released. The release signaling     steps 435-38 will be discussed in detail with reference to FIG. 14.

FIG. 11 is a signal flow diagram illustrating retrieve call features of FIG. 10:

-   403-04 The HLR 52 recognizes the called number as a member of a     multiple-termination routing and that, based on the received     TransactionCapability parameter the Originating MSCe 48, is capable     of supporting a multiple-termination routing to a plurality of     potential terminating devices. In this case, the first member in the     member list (that is, the mobile station 40) is registered in     another system; therefore, a ROUTREQ is sent to the visitor location     register 54, which forwards the ROUTREQ to the Serving MSCe 50. -   405-06 In response to the ROUTREQ, the Serving MSCe 50 checks its     internal data structures and determines that the mobile station 40     is currently idle (or in similar call-ready states, such as the call     is involved in another call, but has a call waiting feature). The     Serving MSCe 50 allocates a TLDN and returns this information to the     visitor location register 54 in a routreq response. The VLR 54 sends     the routreq to the home location register 52.

FIG. 12 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 10. In this sequence of steps, the Originating MSCe 48 receives a SIP provisional response, indicating that the call setup to mobile station 40 is proceeding, from Serving MSCe 50 and acknowledges the reception with a SIP PRACK. Unlike a single termination scenario, when the Originating MSCe 48 receives any 18x messages from Serving MSCe 50 (such as for indicating a desire for local ringback), the 18x message is terminated (that is not forwarded onward to the packet network 22) by the Originating MSCe 48.

-   415 After receiving the INVITE of signaling step 408, if the INVITE     request did not contain an ISUP IAM Message, the Serving MSCe 50 can     send either a 180 Ringing message or a 183 Session Progress message     to the Originating MSCe 48.     -   When the INVITE request includes an ISUP IAM Message, the         Serving MSCe 50 may send either a 180 Ringing message or a 183         Session Progress message including an ISUP ACM message to the         Originating MSCe 48.     -   If the Serving MSCe elects to initiate local ringback then the         180 Ringing message is sent. -   416 In response to the 180 Ringing message or a 183 Session Progress     message of signaling step 415, a PRACK message is sent from the     Originating MSCe 48 to the Serving MSCe 50. -   417 The Serving MSCe 50 sends a 200 OK response to the Originating     MSCe 48 in response to the PRACK message of signaling step 416.

FIG. 13 is a signal flow diagram illustrating the detailed session progress signal sequence of FIG. 10 for connection management. In this sequence of steps, the Originating MSCe 48 receives a SIP provisional response from Serving MSCe 50, indicating that the call setups to mobile station 40 is proceeding, and also acknowledging the Serving MSCe 50 reception of the SIP PRACK message. Unlike a single termination scenario, the Originating MSCe will store any information received (such as SDP messages) in the SIP provisional response and does not act. Only when the Originating MSCe 50 receives information as to which of the terminating devices completes the call setup (signaling step 431 which includes Call-ID1) does the Originating MSCe 50 retrieve the appropriate stored information and send it to the signaling entity supporting the calling party.

-   423 Upon receiving a Reply message in signaling step 422, the     Serving MSCe 50 sends the Originating MSCe 48 a 183 Session Progress     message including SDP-5.     -   Note the 183 Session Progress message is not sent to the         originator of the INVITE message, signaling step 401. -   424 In response to the 183 Session Progress message of signaling     step 423, the Originating MSCe 48 stores SDP-5, and sends a PRACK     message to the Serving MSCe 50. -   425 The Serving MSCe 50 sends a response to the PRACK message of     signaling step 424 to the Originating MSCe 48.

FIG. 14 is a signal flow diagram illustrating the release of the call setups to the remaining potential terminating devices of FIG. 10:

-   435 Upon receiving a 200 OK message (signaling step 431), the     Originating MSCe 48 sends an ISUP REL (Release) message to release     the PSTN call setup. -   436 The Originating MSCe 48 receives an ISUP RLC (Release Complete)     message signaling completion of the PSTN call setup release. -   437 Upon receiving a 200 OK message in signaling step 431, the     Originating MSCe 48 sends the MGW 27 an H.248 message. The H.248     message includes two SUBTRACT commands to remove termination 8 and     termination 9. -   438 The MGW 27 replies to the H.248 message of signaling step 437     with a Reply message.

FIGS. 15 a and 15 b are a signal flow diagram 500 illustrating call delivery for consecutive multiple-termination routing. The example provides two multiple-terminations: the mobile station 40 via the base station 36, and the mobile station 46 via the mobile station 42.

-   501 The Originating MSCe 48 receives an INVITE message including a     SDP message labeled SDP-4 and a called number. The INVITE may     contain an encapsulated ISUP IAM. The Originating MSCe 48 is the     MSCe that owns the called number dialing by the calling party (for     example mobile station 12). -   502 The Originating MSCe 48 sends a LOCREQ to the home location     register 52 associated with the called number. The Originating MSCe     48 may optionally include the TransactionCapability parameter to     specify the appropriate termination handling. -   503-06 The call features associated with the called number are     retrieved via the home location register 52. Retrieval of the call     features will be discussed in detail with reference to FIG. 16. -   507 When the routreqs are received by the home location register 52     from signaling steps 503-06, the HLR 52 returns a locreq to the     Originating MSCe 48. The locreq includes termination routing     information for the first group member in the form of the     TerminationList parameter, along with an indication of the reason     for extending the incoming call (that is, for multiple-termination     routing) in the DMH_RedirectionIndicator (“REDIND”) parameter. In     this scenario the TerminationList member list includes an     intersystem termination for the first member, mobile station 40. The     NATIME (No Answer TIME) parameter indicates, in seconds, the length     of time the Originating MSCe 48 waits before applying a no-answer     treatment to the call setup. -   508 After receiving the locreq from signaling step 507, the     Originating MSCe 48 determines that the intersystem termination is     associated with an MSCe and thus SIP-T/SIP will be used for the call     setup to the MSCe serving the termination device. The Originating     MSCe 48 sends an INVITE message to the Serving MSCe 50 including     Call-ID1, TLDN1 and SDP-4 to setup a call to the member in the     multiple-termination member list (that is, the mobile station 40).     The INVITE can contain an encapsulated ISUP IAM message. Note that     the Originating MSCe 48 can elect to modify SDP-4 as received in     signaling step 501. Note that the INVITE request of this signaling     step is for the establishment of a Dialog between the Originating     MSCe 48 and the Serving MSCe 50, and is a different Dialog than that     related to the INVITE request of signaling step 501 received by the     Originating MSCe 48. The Serving MSCe 50 will use TDLN1 to make the     association with MSID1 received in the ROUTREQ message of signaling     step 504 (see FIG. 16). -   509 After receiving the locreq in signaling step 507, if the INVITE     request of signaling step 501 did not contain an ISUP IAM Message,     the Serving MSCe 50 may send either a 180 Ringing message or a 183     Session Progress message to the originator of the INVITE request     (Step 1).     -   When the INVITE request (Step 501) includes an ISUP IAM Message         the Originating MSCe 48 may send either a 180 Ringing message or         a 183 Session Progress message including an ISUP ACM message to         the originator of the INVITE request of signaling step 501.     -   If the Originating MSCe 48 elects to initiate local ringback,         then a 180 Ringing message is sent. Otherwise, a 183 Session         Progress message is sent. For a call setup to a single         terminating device, the Serving MSCe that serves the terminating         device controls all aspects of ringback to the calling party.         When multiple-termination routing is performed, the control         logic within the Originating MSCe 48 controls all aspects of         ringback to the calling party. Accordingly, in this messaging         exchange, when the call delivery request of signaling step 501         is a SIP INVITE, the Originating MSCe 48 may respond to the         received call delivery request with a ringback message that         instructs the sender of the call delivery request to generate         ringback to the calling party terminating device. -   510 In response to the 180 Ringing or 183 Session Progress message,     a PRACK message is sent to the Originating MSCe 48. -   511 The Originating MSCe 48 sends a 200 OK response to the PRACK     message of signaling step 510. -   512-14 The ringing management between the Originating MSCe 48 and     the Serving MSCe 50 prevents the Serving MSCe from controlling local     ringback to the calling party. Ringing management 512-14 will be     discussed in detail with reference to FIG. 17. -   515 After receiving the INVITE message in signaling step 508, the     Serving MSCe 50 sends an MS PAGING REQUEST message to the base     station 36 to initiate a mobile terminated call setup scenario for     the mobile station associated with TLDN1 (that is, mobile station     40). The PAGING REQUEST message includes the “Desired Codec” for the     mobile station 40. -   516-20 When the terminating mobile station 40 responds to the page,     an IOS PAGING RESPONSE message is sent from the base station 36 to     the Serving MSCe 50. The PAGING RESPONSE message includes the codec     chosen by the mobile station 40. The PAGING RESPONSE message may     contain a list of available base station 36 transcoders, and the     connection information for the base station communications channel     at termination 7. -   521 The Serving MSCe 50 establishes a context with a MGW 26. An     H.248 message is sent from the Serving MSCe 50 to the MGW 26, and     for this example, includes two ADD commands. The first ADD command     establishes a termination for a bearer channel using RTP towards the     packet network 22. The mode is set to sendrecv. If the Serving MSCe     50 elects to initiate Termination-Side ringback, then the MGW 26     initiates ringback from termination 5. The first ADD command     includes SDP-4, which is the remote SDP including the connection     information for the bearer entity supporting the calling party (for     example, the MGW 20 supporting a call initiated by the mobile     station 12). Connection information may include an IP Address and/or     a User Datagram Protocol (“UDP”) port number. Note that the ringback     tone generated by the MGW 26 is not sent to the calling party. As     mentioned in signaling step 509 the originating MSCe 48 controls all     aspects of ringback to the calling party for multiple-termination     routing scenarios. The bearer entity supporting the calling party     will not allow such data to pass to the calling party until the     bearer entity confirms that the data comes from a trusted source     (such as a first responding device). In this manner, erroneous noise     or sound transmission to the calling party is avoided. The     Originating MSCe 48 controls the flow of the messaging to the     network entities that support the calling party. Upon the     Originating MSCe 48 response to the SIP INVITE of signaling step 501     with a 200 OK (INVITE) having an SDP (and the associated connection     information of the trusted source), then the bearer entity     supporting the calling party passes the received bearer data to the     calling party.     -   The first ADD command may also contain a BT (Bearer Timer)         parameter indicating, in seconds, the length of time MGW 26         waits without receiving data from the connection endpoint         defined in SDP-4 before applying an error treatment to         termination 5 (for example removing termination 5 from the         bearer channel using RTP towards the packet network 22 and         sending a message to the Serving MSCe 50 informing it of the         action). The Serving MSCe 50, from the LEGINFO1 parameter in the         Routereq message (signaling step 504), is aware that the call         associated with TLDN1 is one termination of a         multiple-termination routing scenario. In general the call setup         time of a multiple-termination routing scenario is greater than         the call setup time of a single termination scenario. The         Serving MSCe 50 may, on a per call setup basis, adjust the value         of BT based on knowledge it may have about the call setup.     -   The second ADD command establishes a termination for the base         station 36 communication channel with a mode set to sendrecv.         The second ADD command includes SDP-7, which is the remote SDP         including the base station 36 connection information (that is         information sent in signaling step 512 that relates to         termination 7). -   522 The MGW 26 replies to the H.248 message by sending a H.248 Reply     message to Serving MSCe 50. The Reply message includes SDP-5 and     SDP-6. SDP-5 is the local SDP for the termination given in SDP 4 and     includes the MGW 26 connection information for termination 5. SDP-6     is the local SDP for the termination towards the base station 36 and     includes the MGW 26 connection information (for example, IP address     and UDP Port number) for termination 6. -   523-26 The session progress signaling addresses the handshake     operation between the Serving MSCe 50 and the Originating MSCe 48.     The handshake operation between the Originating MSCe 48 and the     Serving MSCe 50 operates to provide connection management for the     call setup. The session progress signaling 523-26 will be discussed     in detail with reference to FIG. 18. -   526-27 After receiving the H.248 Reply message of signaling step     522, the Serving MSCe 50 sends an IOS Assignment Request message to     the base station 36 to request assignment of radio resources. The     Assignment Request message includes the MGW 26 connection     information (for termination 6, obtained from signaling step 522),     request for base station 36 transcoding (if necessary) and the codec     assignment for the mobile station associated with TDLN1.     -   After receiving an Assignment Request message in signaling step         526, the base station 36 sends an IOS Assignment Complete         message to the Serving MSCe 50. -   528-34 After the time value of NATIME in signaling step 507 has been     exceeded, the call setup is released. Details of the release in     signaling steps 528-34 will be discussed in detail with reference to     FIG. 19. -   535 Following a non-completion of the initiated call setup to the     first of the plurality of potential terminating devices (in this     example, the mobile station 40), the Originating MSCe 48, based upon     the instructions in the TERMTRIG (Termination Triggers) parameter of     signaling step 507 sends a TRANUMREQ to the home location register     52. The TRANUMREQ contains a REDREASON (RedirectionReason) parameter     and the BILLID (Billing ID) associated with the first call setup.     The Originating MSCe 48 may optionally include a TRANSCAP     (TransactionCapability) parameter to indicate the Originating MSCe     50 transaction capability at the current time. -   536-39 The next call features associated with the called number with     respect to consecutively initiated call setups for the remaining     potential terminating devices are retrieved next via the home     location register 52. Retrieval of the call features for signaling     steps 536-39 will be discussed in detail with reference to FIG. 20. -   540 When the routreq is received by the home location register 52 in     signaling steps 536-39, the HLR 52 returns a tranumreq to the     Originating MSCe 48. The tranumreq includes multiple-termination     routing information in the form of the TerminationList parameter,     along with an indication of the reason for extending the incoming     call (that is, for consecutively initiated multiple-termination     routing) in the REDIND (DMH_RedirectionIndicator) parameter. In this     scenario the TerminationList parameter includes the next termination     for consecutively initiating terminations (that is, mobile station     46). -   541 After receiving the tranumreq response from signaling step 540,     the Originating MSCe 48 determines that the intersystem termination     is associated with a MSCe, and that SIP-T/SIP is used for the call     setup to the MSCe serving the termination device. The Originating     MSCe 48 sends to the Serving MSCe an INVITE message that includes     Call-ID2, TLDN2 and SDP-4 to setup a call to the second member of     the member list (that is, the mobile station 46). The INVITE can     include an encapsulated ISUP IAM message. Note that the Originating     MSCe 48 can elect to modify SDP-4 as received in signaling step 501.     Also, the INVITE request for this signaling step establishes a     Dialog between the Originating MSCe 48 and the Serving MSCe 50, and     is a different Dialog than that related to the INVITE request of     signaling step 501, received by the Originating MSCe 48. The Serving     MSCe 50 uses TDLN2 to make the association with MSID2 received in     the ROUTREQ message of signaling step 537. -   545-47 The ringing management between the Originating MSCe 48 and     the Serving MSCe 50 prevents the Serving MSCe from controlling local     ringback to the calling party. Ringing management 545-47 will be     discussed in detail with reference to FIG. 21. -   548 After receiving an INVITE message in signaling step 541, the     Serving MSCe 50 sends to the base station 42 an IOS PAGING REQUEST,     which initiates a mobile terminated call setup scenario for the     mobile station associated with TLDN2 (that is, mobile station 46).     The PAGING REQUEST message includes the “Desired Codec” for mobile     station 46 -   549 When the mobile station 46 responds to the page, an IOS PAGING     RESPONSE message is sent from the base station 42 to the Serving     MSCe 50. The PAGING RESPONSE message includes the codec chosen by     the terminating mobile. The PAGING RESPONSE message may contain a     list of available base station transcoders, and the connection     information for the base station 42 communications channel at     termination 11. -   555 The Serving MSCe 50 establishes a context with a MGW 27. An     H.248 message is sent from Serving MSCe 50 to the MGW 27 including     two ADD commands. The first ADD command establishes a termination     for a bearer channel using RTP towards the packet network 22. The     mode is set to sendrecv. If the Serving MSCe 50 elects to initiate     Termination-Side ringback, the MGW 27 initiates ringback from     termination 9. The first ADD command includes SDP-4, which is the     remote SDP including the connection information for the bearer     entity supporting the calling party (for example MGW 20 supporting a     call initiated by mobile station 12). Connection information may     include an IP Address and a User Datagram Protocol (“UDP”) Port     number.     -   Note that the MGW 26 generates a ringback tone that will not be         received by the calling party. As mentioned in step 509 the         Originating MSCe 48 controls all aspects of ringback to the         calling party for multiple-termination routing scenarios. The         bearer entity supporting the calling party will not allow         received data to be passed to the calling party until the bearer         entity is assured that the data is coming from a trusted source         (such as a first responding terminal). The Originating MSCe 48         controls the flow of all messaging to the network entities         support the calling party. As an example of a trusted source,         the bearer entity that supports the calling party passes         received bearer data (such as voice/sound data) to the calling         party when a 200 OK (INVITE) including a SDP (with the         connection information of the trusted source) sent by the         Originating MSCe 48 in response to the SIP INVITE of signaling         step 501.     -   The first ADD command may also contain a BT (Bearer Timer)         parameter indicating, in seconds, the length of time MGW 27         waits without receiving data from the connection endpoint         defined in SDP-4 before applying an error treatment to         termination 9 (for example removing termination 9 from the         bearer channel using RTP towards the packet network 22 and         sending a message to the Serving MSCe 50 informing it of the         action). The Serving MSCe 50, from the LEGINFO2 parameter in the         Routereq message (signaling step 537), is aware that the call         associated with TLDN2 is one termination of a         multiple-termination routing scenario. In general the call setup         time of a multiple-termination routing scenario is greater than         the call setup time of a single termination scenario. The         Serving MSCe 50 may, on a per call setup basis, adjust the value         of BT based on knowledge it may have about the call setup.     -   The second ADD command establishes a termination for the base         station 42 communication channel with a mode set to sendrecv.         The second ADD command includes SDP-7, which is the remote SDP         including the base station 42 connection information (that is,         information sent in signaling step 547 that relates to         termination 11). -   556 The MGW 27 replies to the H.248 message by sending a H.248 Reply     message to Serving MSCe 50. The Reply message includes SDP-9 and     SDP-10. SDP-9 is the local SDP for the termination given in SDP-4     and includes the MGW 27 connection information for termination 9.     SDP-10 is the local SDP for the termination towards the base station     42 and includes the MGW 27 connection information (for example, IP     address and UDP Port number) for termination 10. -   557-59 The session progress signaling addresses the handshake     operation between the Serving MSCe 50 and the Originating MSCe 48,     which provides connection management for the call setup. The session     progress signaling 557-59 will be discussed in detail with reference     to FIG. 22. -   560-61 After receiving the H.248 Reply message of signaling step     556, the Serving MSCe 50 sends an IOS Assignment Request message to     the base station 42 to request assignment of radio resources. The     IOS Assignment Request message includes the MGW 27 connection     information (for termination 10, obtained from signaling step 556),     request of any base station 42 transcoding (if necessary) and the     codec assignment for the mobile station associated with TDLN2.     -   After receiving an IOS Assignment Request message from signaling         step 560, the base station 42 sends an IOS Assignment Complete         message to the Serving MSCe 50. -   562 The base station 42 sends an IOS CONNECT message to the Serving     MSCe 50 to indicate that the call has been answered by the mobile     station associated with TLDN2 (that is, mobile station 46). -   563 If the Serving MSCe 50 elected in signaling step 555 to initiate     Termination-Side ringback, then the Serving MSCe 50 sends a H.248     message to MGW 27. The H.248 message contains a MODIFY command to     deactivate Termination-Side Ringback. -   564 MGW 27 acknowledges the H.248 message of signaling step 562 by     sending a H.248 Reply message to Serving MSCe 50. -   565 After receiving the CONNECT message from the base station 42 and     the PRACK message is received in signaling step 558 (see FIG. 22),     the Serving MSCe 50 sends a 200 OK message to the Originating MSCe     48. When the INVITE request of signaling step 541 includes an ISUP     IAM Message, then the 200 OK message can contain an ISUP ANM     message. The 200 OK (INVITE) message acknowledges that the INVITE of     signaling step 541 has succeeded. -   566 Upon receiving a 200 OK message in signaling step 565, the     Originating MSCe 48 sends a 200 OK message to the originator of the     INVITE request of signaling step 501. Since the intersystem     termination (that is, the mobile station 46) first answered and/or     responded, the 200 OK message includes SDP-9 (that is the SDP     received in signaling step 556). When the INVITE request of     signaling step 501 includes an ISUP IAM message, then the 200 OK     message can contain an ISUP ANM Message. The 200 OK message     acknowledges that the INVITE of signaling step 501 message has     succeeded. -   567 The Originating MSCe 48 receives an ACK message. The ACK message     confirms reception of the final response (that is, the 200 OK     message of signaling step 566) for the Dialog identified by     Call-ID0. -   566 Upon receiving an ACK message in signaling step 567 for the     Dialog identified by Call-ID0, the Originating MSCe 48 sends an ACK     message to the Serving MSCe 50 to confirm reception of the final     response (that is, 200 OK message of signaling step 566) for the     Dialog identified by Call-ID2.

FIG. 16 is a signal flow diagram illustrating the retrieve call features signal sequence of FIG. 15 a:

-   503-04 The HLR 52 recognizes the called number as a member of a     multiple-termination routing and that, based on the received     TransactionCapability parameter the Originating MSCe 48, is capable     of supporting a multiple-termination routing to a plurality of     potential terminating devices. In this case, the first member in the     member list (that is, the mobile station 40) is registered in     another system; therefore, a ROUTREQ is sent to the VLR 54, which     forwards the ROUTREQ to the Serving MSCe 50. -   505-06 In response to the ROUTREQ, the Serving MSCe 50 checks its     internal data structures and determines that the mobile station 40     is currently idle (or in similar call-ready states, such as the call     is involved in another call, but has a call waiting feature). The     Serving MSCe 50 allocates a TLDN and returns this information to the     VLR 54 in a routreq response. The VLR 54 sends a routreq to the HLR     52.

FIG. 17 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 15 a:

-   512 After receiving the INVITE of signaling step 508, if the INVITE     request did not contain an ISUP IAM Message, the Serving MSCe 50 may     send either a 180 Ringing message or a 183 Session Progress message     to the Originating MSCe 48     -   When the INVITE request includes an ISUP IAM Message, the         Serving MSCe 50 may send either a 180 Ringing message or a 183         Session Progress message including an ISUP ACM message to the         Originating MSCe 48.     -   If the Serving MSCe elects to initiate local ringback then the         180 Ringing message is sent. -   513 In response to the 180 Ringing message or a 183 Session Progress     message of signaling step 512, a PRACK message is sent from the     Originating MSCe 48 to the Serving MSCe 50. -   514 The Serving MSCe 50 sends a 200 OK response to the Originating     MSCe 48 in response to the PRACK message of signaling step 513.

FIG. 18 is a signal flow diagram illustrating the detailed session progress signal sequence of FIG. 15 a:

-   523 Upon receiving a H.248 Reply message to the ADD message in     signaling step 522, the Serving MSCe 50 sends the Originating MSCe     48 a 183 Session Progress message including SDP-5.     -   Note the 183 Session Progress message is not sent to the         originator of the INVITE message, signaling step 501. -   524 In response to the 183 Session Progress message of signaling     step 523, the Originating MSCe 48 stores SDP-5, and sends a PRACK     message to the Serving MSCe 50. -   525 The Serving MSCe 50 sends a response to the PRACK message of     signaling step 524 to the Originating MSCe 48.

FIG. 19 is a signal sequence illustrating releasing the call setup of a potential terminating-device of FIG. 15 a:

-   528 Following the passage of a time period given by the NATIME     parameter of signaling step 507, the Originating MSCe 48 abandons     the call setup attempt with mobile station 40. The Originating MSCe     48 sends a IOS CANCEL message to the Serving MSCe 50. When the     INVITE request of signaling step 508 included an ISUP IAM Message     then the CANCEL message may contain a ISUP REL message. -   529 The Serving MSCe 50 sends a 487 Request Terminated message to     the Originating MSCe 48. The 487 Request Terminated message is a     response to the INVITE request of signaling step 508. -   530 The Serving MSCe 50 answers the CANCEL request of signaling step     528 by sending a 200 OK message to the Originating MSCe 48. -   531 Upon receiving a CANCEL message of signaling step 528 from the     Originating MSCe 48, the Serving MSCe 50 starts releasing all     resources associated with the call attempt to MSID-1 (that is,     mobile station 40). The Serving MSCe 50 sends the MGW 26 a H.248     message consisting of two SUBTRACT commands. The first SUBTRACT     command removes termination 6 to base station 36. The second     SUBTRACT removes termination 5 for the bearer channel using RTP     towards the packet network 22. -   532 The MGW 26 replies to the H.248 message at signaling step 531     with a H.248 Reply message. -   533 Upon receiving a CANCEL message at signaling step 528 from the     Originating MSCe 48, the Serving MSCe 50 sends an IOS Clear Command     to base station 36, instructing the base station 36 to release the     associated dedicated resources. -   534 The base station 36 sends an IOS Clear Complete message to the     Serving MSCe 50. The Serving MSCe 50 releases the underlying     transport connection.

FIG. 20 is a signal flow diagram illustrating the next call features retrieval of signaling steps 536-539 of FIG. 15 b:

-   536-37 Upon receiving the TRANUMREQ from the Originating MSCe 48,     the HLR 52 recognizes the Billing ID or the PilotNumber (the called     number for signaling step 501) to relate the request to the     information provide in the locreq, signaling step 507. The HLR 52     associates the PilotNumber to the multiple-termination routing     feature, and that, based on the received TransactionCapability     parameter, the Originating MSCe 48 is capable of supporting a     multiple-termination call. In this case, the second MSID in the     member list (that is, mobile station 46) is registered in the same     network system as MSID2. A ROUTREQ is sent to the VLR 54, which     forwards the ROUTREQ to the Serving MSCe 50. -   538-39 In response to the ROUTREQ, the Serving MSCe 50 checks its     internal data structures and determines that the mobile station 46     is currently idle (or in similar call-ready states, such as the call     is involved in another call, but has a call waiting feature). The     Serving MSCe 50 then allocates a TLDN2 and returns this information     to the VLR 54 in a routreq. The VLR 54 sends a routreq to the home     location register 52.

FIG. 21 is a signal flow diagram illustrating the ringing management signal sequence of FIG. 15 b:

-   545 After receiving the INVITE of signaling step 541, if the INVITE     request did not contain an ISUP IAM Message, the Serving MSCe 50 may     send either a 180 Ringing message or a 183 Session Progress message     to the Originating MSCe 48.     -   When the INVITE request includes an ISUP IAM Message, the         Serving MSCe 50 may send either a 180 Ringing message or a 183         Session Progress message including an ISUP ACM message to the         Originating MSCe 48.     -   If the Serving MSCe elects to initiate local ringback then the         180 Ringing message is sent. -   546 In response to the 180 Ringing message or a 183 Session Progress     message of signaling step 512, a PRACK message is sent from the     Originating MSCe 48 to the Serving MSCe 50. -   547 The Serving MSCe 50 sends a 200 OK response to the Originating     MSCe 48 in response to the PRACK message of signaling step 548.

FIG. 22 is a signal flow diagram illustrating the detailed session progress signal sequence of FIG. 15 b. The Originating MSCe 48 coordinates the multiple-termination routing for connection management. Generally, the signal flow of FIG. 22 reflects that the Serving MSCe 50 seeks to move the ringback to the terminating end of a call. When the Serving MSCe 50 does not seek to move the ringback to the terminating end of a call, the Serving MSCe 50 provides a 180 Ringing message with alert information (to update the SDP and to indicate to continue ringing).

As one of ordinary skill in the art would appreciate, the SDP may also be updated at a later point (such as with the 200 OK (Invite) at signaling step 564). Note that even through the Serving MSCe 50 might seek to initiate termination-side ringback, the Originating MSCe 48 controls all aspects of ringback to the calling party for multiple-termination routing scenarios. The bearer entity supporting the calling party will not pass received data to the calling party until the bearer entity is assured that the data is coming from a trusted source. The Originating MSCe 48 controls the flow of all messaging to the network entities support the calling party. In the present example, the bearer entity will pass received bearer data to the calling party when the Originating MSCe 48 sends a 200 OK (INVITE) including a SDP (with the connection information of the trusted source) in response to the SIP INVITE of signaling step 501.

-   559 Upon receiving a H.248 Reply message to the ADD message in     signaling step 556, the Serving MSCe 50 sends the Originating MSCe     48 a 183 Session Progress message including SDP-9. -   560 In response to the 183 Session Progress message of signaling     step 559, the Originating MSCe 48 stores SDP-9, and sends a PRACK     message to the Serving MSCe 50. -   561 The Serving MSCe 50 sends a response to the PRACK message of     signaling step 560 to the Originating MSCe 48.

FIG. 23 is a flow diagram of a method 600 for multiple-termination routing in a wireless environment that includes an Internet Protocol (“IP”) core. Beginning at step 602, a call delivery request is received. The call delivery request is based upon intelligent network protocols and includes a called number. In this regard, the call delivery request may be based on ISUP protocols (for example, from a PSTN network 32) or based on SIP protocols (for example, a SIP INVITE request from a packet network 22).

With the called number, associated call features are retrieved at step 604. The call feature retrieval uses ANSI-41 protocols, such as with a LOCREQ (LocationRequest) invoke message, which returns an ANSI-41 location request response (“locreq”). Within the location request response are the call features associated with the called number.

At step 608, a determination is made as to whether the call features include multiple-termination routing information to a plurality of potential terminating devices. The call features include multiple-termination routing information in the form of a parameter, such as a TERMLIST (TerminationList) parameter. The multiple-termination routing information provides a member list of the potential terminating devices, and information indicating when to request further instructions on call processing relating to the device of the plurality of potential terminating devices.

When the call features include multiple-termination routing information at step 610, wherein at least one termination to be setup utilizes Session Initiation Protocol (“SIP”), call setups are initiated to each of the plurality of potential terminating devices. The multiple-termination routing information provides the manner and/or sequence for initiating the call setups.

For example, the initiation of the call setup to each of the plurality of potential terminating devices may be conducted consecutively. The received call setup provisional responses (for example, those including a session description protocol (SDP)) provides connection information used for establishing a bearer path (that is, a path for voice and/or data) for the call setup. Upon detection of a first potential terminating device to complete the call setup, initiation of subsequent call setups is foregone to any remaining potential terminating devices.

As another example, the initiation of the call setup to each of the plurality of potential terminating devices may be conducted concurrently. The received provisional responses (for example, those including a session description protocol (SDP)) for each call setup provides connection information used for establishing a bearer path (that is, a path for voice and/or data) for the call setup. Upon detection of a first potential terminating device to complete the call setup, call setups is to any of the remaining potential terminating devices is released.

The invention disclosed herein is susceptible to various modifications and alternative forms. Specific embodiments therefore have been shown by way of example in the drawings and detailed description. It should be understood, however, that the drawings and the detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the claims. 

1. A method for multiple-termination routing in a wireless network environment, the method comprising: receiving a call delivery request, wherein the call delivery request includes a called number; determining call features associated with the called number; determining whether the call features include multiple-termination routing information to a plurality of potential terminating devices; and when the call features include multiple-termination routing information including at least one termination to be routed utilizing Session Initiation Protocol (“SIP”), initiating a call setup to each of the plurality of potential terminating devices.
 2. The method of claim 1, further comprising: when the call delivery request is a SIP INVITE, responding to the received call delivery request with a ringback message, wherein the ringback message instructs the sender of the call delivery request to generate ringback to the calling party terminating device.
 3. The method of claim 1, wherein said initiating a call setup to each of the plurality of potential terminating devices comprises: consecutively initiating the call setup to each of the plurality of potential terminating devices; extending a call setup leg to the consecutively initiated call setups in response to a received provisional response, wherein the received provisional response provides call connection information to be used for establishing a bearer path; and upon detecting a first potential terminating device to complete the call setup, foregoing initiation of the subsequent call setup to any of the remaining potential terminating devices.
 4. The method of claim 1, wherein said initiating the call setup to each of the plurality of potential terminating devices comprises: concurrently initiating the call setup to each of the plurality of potential terminating devices; extending a call setup leg to each of the concurrently initiated call setups in response to a received provisional response, wherein the received provisional response provides call connection information that is to be used for establishing a bearer path; and upon detecting a first potential terminating device to complete the call setup, releasing the call setup to any of the remaining potential terminating devices.
 5. The method of claim 1, wherein the multiple-termination routing information comprises: a member list providing the plurality of potential terminating devices; and information indicating when to request instructions on call processing relating to a device of the plurality of potential terminating devices.
 6. The method of claim 1, further comprising: when the potential terminating device is a PSTN-protocol based device, sustaining signaling communication with a media gateway for enabling the PSTN-protocol based device to interwork with the IP core while initiating the call setup to each of the plurality of potential terminating devices.
 7. The method of claim 6, further comprising: providing timing information as to when to invoke error treatment for a plurality of bearers for the call setup.
 8. A switching center, comprising: one or more processors; and one or more memory mediums coupled to the one or more processors, wherein the one or more memory mediums store program instructions that are executable by the one or more processors to: receive a call delivery request, wherein the call delivery request includes a called number; determine call features associated with the called number; determine whether the call features include multiple-termination routing information to a plurality of potential terminating devices; and when the call features include multiple-termination routing information including at least one termination to be routed utilizing Session Initiation Protocol (“SIP”), initiate a call setup to each of the plurality of potential terminating devices.
 9. The switching center of claim 8, wherein the program instructions are further executable to: when the call delivery request is a SIP INVITE, respond to the received call delivery request with a ringback message that instructs the sender of the call delivery request to generate ringback to the calling party terminating device.
 10. The switching center of claim 8, wherein the program instructions are further executable to: consecutively initiate the call setup to each of the plurality of potential terminating devices; extend a call setup leg to the consecutively initiated call setups in response to a received provisional response, wherein the received provisional response provides call connection information to be used for establishing a bearer path; and upon detecting a first potential terminating device to complete the call setup, foregoing initiation of a subsequent call setup to the remaining potential terminating devices.
 11. The switching center of claim 8, wherein the program instructions are further executable to: concurrently initiate the call setup to each of the plurality of potential terminating devices; extend a call setup leg to each of the concurrently initiated call setups in response to a received provisional response, wherein the received provisional response provides call connection information that is to be used for establishing a bearer path; and upon detecting a first potential terminating device to complete the call setup, release the call setup to any of the remaining potential terminating devices.
 12. The switching center of claim 8, wherein the multiple-termination routing information comprises: a member list providing the plurality of potential terminating devices; and information indicating when to request instructions on call processing relating to a device of the plurality of potential terminating devices.
 13. The switching center of claim 8, wherein the program instructions are further executable to: when the potential terminating device is a public switched telephone network (PSTN)-protocol based device, sustain signaling communication with a media gateway for enabling the PSTN-protocol based device to interwork with an Internet Protocol (“IP”) core while initiating the call setup to each of the plurality of potential terminating devices.
 14. A non-transitory, computer accessible memory medium storing program instructions for multiple-termination routing in an wireless network, wherein the program instructions are executable by a processor to: receive a call delivery request, wherein the call delivery request includes a called number; determine call features associated with the called number; determine whether the call features include multiple-termination routing information to a plurality of potential terminating devices; and when the call features include multiple-termination routing information including at least one termination to be routed utilizing Session Initiation Protocol (“SIP”), initiate a call setup to each of the plurality of potential terminating devices.
 15. The non-transitory, computer accessible memory medium of claim 14, wherein the program instructions are further executable to: when the call delivery request is a SIP INVITE, respond to the received call delivery request with a ringback message, wherein the ringback message instructs the sender of the call delivery request to generate ringback to the calling party terminating device.
 16. The non-transitory, computer accessible memory medium of claim 14, wherein said initiating a call setup to each of the plurality of potential terminating devices comprises: consecutively initiating the call setup to each of the plurality of potential terminating devices; extending a call setup leg to the consecutively initiated call setups in response to a received provisional response, wherein the received provisional response provides call connection information to be used for establishing a bearer path; and upon detecting a first potential terminating device to complete the call setup, foregoing initiation of the subsequent call setup to any of the remaining potential terminating devices.
 17. The non-transitory, computer accessible memory medium of claim 14, wherein said initiating the call setup to each of the plurality of potential terminating devices comprises: concurrently initiating the call setup to each of the plurality of potential terminating devices; extending a call setup leg to each of the concurrently initiated call setups in response to a received provisional response, wherein the received provisional response provides call connection information that is to be used for establishing a bearer path; and upon detecting a first potential terminating device to complete the call setup, releasing the call setup to any of the remaining potential terminating devices.
 18. The non-transitory, computer accessible memory medium of claim 14, wherein the multiple-termination routing information comprises: a member list providing the plurality of potential terminating devices; and information indicating when to request instructions on call processing relating to a device of the plurality of potential terminating devices.
 19. The non-transitory, computer accessible memory medium of claim 14, wherein the program instructions are further executable to: when the potential terminating device is a PSTN-protocol based device, sustain signaling communication with a media gateway for enabling the PSTN-protocol based device to interwork with the IP core while initiating the call setup to each of the plurality of potential terminating devices.
 20. The non-transitory, computer accessible memory medium of claim 19, wherein the program instructions are further executable to: provide timing information as to when to invoke error treatment for a plurality of bearers for the call setup. 